PhotoSat 1m elevation image of a tailings beach, with 15cm vertical accuracy

The Challenge of Mine Tailings Beaches and Elevation Mapping

Mine tailings beaches are notoriously difficult to monitor. They’re the hardest surveying task at a mine. Data needs to be up to date, but tailings ponds can be huge: Suncor’s tailings ponds cover over 30 square kilometers. Ground survey teams can’t get close enough for safety reasons, and aerial LiDAR data delivery can be frustratingly slow. Low-flying drones are challenged by cold weather, and cannot cover much distance in a day, so are not reliable when measurements are required for a larger area on the same day.

That’s the challenge Suncor faced at its Alberta oil sands mine. Surveying Suncor’s Tailings Reduction Operation (TRO) site meant getting accurate data quickly over a mine site covering over 270 square kilometers. And when Suncor tried using traditional GPS, they found that only about 20% of the site was safe for crews to access. The next step was to try 3D laser scanners, but these simply couldn’t produce enough data fast enough; multiple set-ups were required and yielded sparse data that required significant processing to be comprehensible and usable. This meant adding to an already too-long wait time, as well as additional expense.

Elevation mapping solutions

PhotoSat’s 15cm accuracy satellite topography (DEM) addresses the challenge. Because we use high accuracy satellites, the data is collected safely and easily, reducing the need for ground crews to expose themselves to hazards. And we can collect satellite photos anywhere in the world, making them ideal for remote or challenging terrain.

50cm satellite ortho photo

50cm resolution satellite ortho photo of a tailings beach. © DigitalGlobe 2013

 

PhotoSat elevation image of a tailings beach

PhotoSat 1m elevation image of a tailings beach, with 15cm vertical accuracy

 

Once the satellite imagery has been acquired, we run it through our unique processing system, developed for the industry by us from seismic data processing tools, with engineers in mind.

We have proven the accuracy of our elevation mapping using tens of thousands of ground control points as comparison. Numerous proof of accuracy studies are available on our website.

We map the entire Suncor site every two weeks, providing usable elevation surveys only five days after data acquisition for use in Suncor’s bi-weekly engineering meetings. Our satellite mapping provides an instantaneous snapshot of the entire tailings beach waterline, the geometry of the beaches, and the height of the tailings dykes. We continue to map the Suncor Millennium and Steepbank mines every two weeks, including mapping the Mature Fine Tailings cells in thickness increments of 15cm.

The digital elevation models are also used for mapping windrows, monitoring tailings dykes, calculating volume changes, and verifying the locations of as-built infrastructure. When Suncor’s tailings engineers need to make a decision, they have the reliable, up-to-date data to base it on.

The original presentation made my Suncor at the 2014 Trimble conference that compares PhotoSat mapping to alternatives, can be viewed here.

To learn more or get a quote for topographic mapping for your resource project, contact us at info@photosat.ca or 1-604-681-9770.

Toes and crests, satellite image

Automatic toes & crests mapping at Suncor’s oil sands mine

In this article we’ll look at how the engineers at Suncor have adopted our toes and crests mapping as an integral part of their mine planning process. This is the last post in a 3 part Suncor case study series. In the first post, we discussed Suncor’s comparison of various survey methods, and in the second article we showed how they use satellite elevation mapping for monitoring mature fine tailings.

Mapping of toes and crests is important for monitoring open-pit mining. On the ground, vehicular access, overburden removal and bench integrity needs to be ascertained if the mine is to continue to be profitable and safe. But on the ground is the worst place for surveyors to be: survey teams that examine mine sites directly are exposed to hazards like falling debris and bench wall slumping as well as heavy vehicle traffic. Which is where PhotoSat comes in.

In collaboration with Suncor, PhotoSat has developed a process to automatically map toes and crests to an accuracy of 15cm without survey teams requiring access to hazardous areas of the mine site. Production isn’t interrupted, surveyors are working on tasks that actually require boots on the ground, and accurate mapping of toes and crests allows the engineers to monitor bench integrity and check mine progression against projections.

Toes and crests over a satellite photo

Toes and crests data draped over a satellite photo

 

Toes and crests over PhotoSat’s elevation image

Toes and crests data draped over PhotoSat’s elevation image

 

Bird’s eye view of toes and crests over a mine site

Bird’s eye view of toes and crests data over a mine site

 

Mine planning often takes place on a biweekly or monthly basis, reflecting production speed. We’re able to supply our oil sands clients with useable data within 5 days, meaning analysis of progress and erosion is more granular and data is available in a timely manner.

There are several mine surveying options on the market, many of which Suncor has tried (see our first post for Suncor’s comparison of various surveying methods). Typically these rely on LiDAR, which uses reflected laser light to build images. Terrestrial laser scanning involves survey teams setting up and using multiple scanning stations and consequently requires more time to produce images. And survey teams are still on the ground! Aerial LiDAR avoids this issue but results in huge point clouds that have to be processed before an image is usable, which can take a very long time. GPS survey equipment can also be used, but data paucity and safety remain serious issues.

Using satellites, Photosat offers instantaneous snapshots of all mine site toes and crests derived from our elevation grids. Our proprietary geophysical processing system results in far greater accuracy than conventional satellite mapping processes such as photogrammetry.

Oil sands mines change fast and digital vector data for toes and crests are vital to the engineers for keeping track of what is usually softer rock. Suncor switched over to using PhotoSat’s satellite topography as their main survey method in 2013. While some areas of the mine still use GPS surveying, toe and crest mapping has been carried out exclusively by PhotoSat.

Our elevation mapping is also used for other applications at oil sands and hard rock mines, such as:

  • Sloughing in nonactive areas
  • Pipelines and roads
  • Power poles
  • Buildings and structures
  • In-pit geotech surveying
  • Correcting LiDAR issues

For more information on satellite elevation mapping and toes and crests, feel free to contact us at info@photosat.ca or 604-681-9770.