While Amazon and others continue to explore drone delivery service, Golder is increasingly deploying unmanned aerial vehicles (UAV, also known as drones) for complex aerial surveys, underground site work, ground condition monitoring and site mapping.
The technical advantages of UAV use continue to unfold as we learn new and different ways to process the data – geotagged images allow for input into GIS systems and photogrammetry packages which produce 3-D models. The models can be used in advanced numeric modeling and for change detection. Advantages in safety for employees are evident too, allowing detailed survey work where ground conditions are uncertain, or sites have poor access.
Perhaps one of the most compelling advantages of UAV use, however, is its ability to bring sites to life for the clients and other key stakeholders, especially with major infrastructure and site development work. Fly-over videos provide new perspectives. Realistic 3-D models and interactive graphics presentations become excellent communications tools in community and stakeholder meetings. We’re able to tell the story of a site in greater detail and gain greater understanding among stakeholders and regulators.
Legal UAV Use in Geological and Environmental Engineering
Since first forming our fixed-wing UAV fleet in Canada, we’ve added multiple quadcopters, including those specially equipped to work underground. We typically deploy fixed-wing UAVs for large area survey work and quadcopter UAVs for smaller sites or other hard- to-reach inspection and survey work.
Commercial UAV use requires trained UAV pilots and, in Canada, involves special permits or exemptions. Regulations vary from country to country and from location to location. It’s essential to become a legal UAV operator in your work’s location, or subcontract to a licensed UAV firm. We’ve secured the necessary permits for Golder in multiple regions, and where permits are still pending, we use licensed third party operators.
Ideal Applications for UAV Use
Golder has utilized UAVs for numerous missions across Canada, the United States, Mexico, Haiti, Brazil, St. Lucia, Ghana, the Ivory Coast, Italy and Australia. These surveys have been used to support mine tailings beach assessments, material stockpile quantity estimates, slope stability inspection, general mapping of sites and more.
UAVs are often a viable alternative technology to traditional topographic surveys, LiDAR aerial surveys, or satellite imagery. In other cases, a UAV survey may be a safer alternative to conventional field team work.
From inspection of water supply tunnels in hydroelectric generating stations, to risk assessment of steep and winding highways across mountains, to thermal imaging of underground water inflows and fish habitats, UAVs are providing additional details to drive better designs, risk assessments, construction and maintenance.
Here are a few more of our challenging applications:
- Survey work in underground mines: UAVs can travel between 40 up to 100 meters depending on the excavation geometry involved.
- Maintenance inspection in tunnels: Quadcopter UAVs can hover directly under the 6-meter-tall (about 18 feet) tunnel crowns, providing critical data.
- Measurement of erosion in steep cliff overhangs: No need for rappelling cliffs. The UAV provided exceptional, high resolution photography safely and in less time.
- Emergency flood monitoring: Golder UAVs provided information on ground conditions during the June 2013 flood in Alberta, Canada, as well as documented conditions pre- and post-construction of bank protection measures.
- Tailings breach monitoring and remediation: Following tailings dam breaches in Canada and Brazil, Golder UAVs were used for videography to assist with stakeholder communication.
Transforming Thousands of Data Points Into Usable Information
Survey UAV cameras take overlapping plan view images from the air while flying 10 to 90 meters (30 to 300 feet) above the ground. The images are stitched together and geo-referenced to produce imagery with a 3D point resolution as fine as 2 centimeters.
Photogrammetry software is then used to produce a 3D digital surface model with about 10-centimeter vertical accuracy in most terrain when tied into temporary ground control points.
We’re able to generate 3-D PDFs, containing comments, that we can email to the client and essentially provide a tour of the site. This often helps better define the scope of work upfront. UAV use during the project helps us refine engineering designs, fine-tune risk assessments and move through permitting and approval processes more quickly.
If you’d like to talk about how UAVs could benefit your project, please feel free to contact me at [email protected].
ABOUT THE AUTHOR
Ryan Preston, M.Sc., P. Eng, is a geological engineer specializing in rock mechanics and remote sensing in both surface and underground settings. He designed and built Golder’s first underground UAV. Ryan holds a master’s of science degree in Engineering Geology with a concentration in photogrammetry and remote sensing applications from Simon Fraser University in Burnaby, Canada. He has a bachelor’s degree in Applied Science Geological Engineering from the University of British Columbia, Vancouver. Ryan is also a licensed professional engineer in Alberta and British Columbia.