wv3 accuracy study with histogram

The spark that ignited the PhotoSat accuracy studies

wv3 accuracy study with histogram

2016 PhotoSat WorldView-3 satellite surveying accuracy study, Asmara, Eritrea.

“Everything that the last speaker just told you is wrong”.   This shocked me since I was the last speaker.  I was just rejoining the audience after my presentation at a satellite data distributors’ conference in San Diego in 2008.

I had given a presentation on PhotoSat’s experience using satellite photos for elevation mapping.  I had shown comparisons between PhotoSat stereo IKONOS satellite elevation mapping and hundreds of mining exploration drill  collar elevations.  Our results suggested an IKONOS mapping accuracy of better than 1.0m in elevation.

The speaker who followed me showed the published specifications of the IKONOS satellite.  He declared that this proved that the results I had just shown were impossible. Then he went on to talk about his own stereo IKONOS mapping results.  His results showed 5m to 10m in elevation mapping accuracy.

 

Looking for a way to unambiguously measure our accuracy

The speaker who challenged PhotoSat’s results in the San Diego meeting actually did us a huge favor.  Although it did not feel like that as I sat fuming in my chair.  His comments provided the motivation for me to find a way to prove we were right.  After this meeting we set about looking for a way to unambiguously demonstrate the accuracy of the PhotoSat stereo satellite elevation mapping.

 

Searching for a detailed, high quality, ground survey data set

We concluded that to prove our accuracy we needed to find a highly accurate ground survey data set covering hundreds of square kilometers. But where to find it?

About two months later, a light came on.  I realized that we might find the elevation survey data that we needed from a large, regional, mining exploration gravity survey.  The topographic surveys associated with mining exploration gravity surveys are among the most accurate and carefully checked topographic surveys in the world.

 

An old friend tells me about an existing ground survey data set

I phoned Kevin MacNabb, president of MWH Geo-Surveys International.  Kevin did gravity survey contracts for me when I was a geophysicist at BP.  I said “Kevin, I am looking for a large regional gravity survey with thousands of accurate topographic survey points.  I want to use the topographic survey data to measure the accuracy of PhotoSat’s stereo IKONOS satellite mapping.”

I added “it would be great if the data is in an area of sparse vegetation in a remote region of the world.  This way we can prove the accuracy of our stereo satellite topographic mapping and show that we can do this anywhere in the world.”

Kevin replied “how would 45,000 ground survey points covering over a thousand square kilometers just west of Asmara, Eritrea do?”  For us this was the perfect data set. Eritrea was a challenging place to work.  It had just emerged from a civil war.  A perfect place to be mapping from satellites. For a fuller description, click this link.

 

Eritrea differential GPS survey crew and equiptment

Asmara Project, Eritrea. MWH Geo-Surveys differential GPS survey crew and equipment. Over 45,000 ground points were surveyed between 2004 and 2008. The Magellan RTK base with a ProMarkTM 500 GPS rover are shown in this photo.

 

The Eritea ground survey data is owned by an existing PhotoSat customer

It turned out that Kevin’s customer for the Eritrea gravity survey, Sunridge Gold, was also a PhotoSat customer for stereo IKONOS mapping.  We negotiated the right to use the 45,000 ground survey points for accuracy studies.  In return, we did some additional stereo IKONOS mapping for the company.

 

PhotoSat’s first comprehensive accuracy study

We were immediately able to use 10,000 of the Eritrea ground survey points to measure the elevation accuracy of 200 km² of stereo IKONOS elevation grid.  PhotoSat had already produced this elevation grid for Sunridge Gold.  We measured the accuracy of the PhotoSat elevation grid as 48cm Root Mean Square Error (RMSE).  The full 2008 IKONOS Eritrea Accuracy study is available to review.

 

PhotoSat accuracy measurement and improvement

Since 2008, PhotoSat has been using the 45,000 Eritrea ground survey points as a test bed to measure accuracy improvements in the PhotoSat processing.  This gives us a quantitative measure of accuracy improvements.  We have shown the results in many conferences and published them.  If there are still disbelievers they are certainly not challenging us publicly.

 

Satellite companies start to provide stereo test data over the Eritrea site.

In 2009, two commercial high resolution satellite companies, GeoEye and DigitaGlobe, provided stereo satellite photos over the PhotoSat Eritrea test area.   The DigitalGlobe data was from the 50cm ground resolution WorldView-1 satellite launched in September 18, 2007.  The GeoEye data was from the 50cm ground resolution GeoEye-1 satellite launched on September 6, 2008.

PhotoSat published elevation mapping accuracy reports for both new satellite systems.  The stereo GeoEye-1 PhotoSat elevation grid had an accuracy of 31cm RMSE, determined by 8,893 ground survey points.  The stereo WorldView-1 PhotoSat elevation grid had an accuracy of 35cm RMSE, determined by over 15,000 ground survey points.

 

WorldView-2 joint DigitalGlobe and PhotoSat news release on Eritrea accuracy study

Soon after the commissioning of the WorldView-2 satellite in early 2010 DigitalGlobe asked PhotoSat to use its new processing system to conduct an accuracy study over the Eritrea test area using stereo WorldView-2 photos.  The PhotoSat Eritrea Accuracy study showed WorldView-2 accuracy of better than 30cm RMSE.  These results were issued on March 16, 2010.  The news release is available here.

 

With accuracy improvement PhotoSat mapping becomes PhotoSat surveying

Once the PhotoSat elevation grids achieved an accuracy of better than 30cm many of our customers began using them in place of ground surveying.  We consequently renamed our products that have accuracy better than 30cm to surveying products.

 

The Eritrea ground survey data set has been used for hundreds of PhotoSat accuracy tests and studies

Since PhotoSat first acquired the 45,000 ground survey points in Eritrea, we have used the data for hundreds of accuracy test and studies.

 

2016 PhotoSat Eritrea accuracy studies

In 2016, we used the current version of the PhotoSat Geophysical Processing System to process a full range a stereo satellite photos over the Eritrea test area.  Some of these results are published on our website on the links below.  The link names include the satellite name, the number of ground control points used in the processing and the RMSE accuracy.

 

WorldView-3, Eritrea, 21 GCP, RMSE 15cm

WorldView-2, Eritrea, 21 GCP, RMSE 14cm

WorldView-3, Eritrea, 2 GCP, RMSE 19cm

WorldView-2, Eritrea, 2 GCP, RMSE 19cm

WorldView-1, Eritrea, 21 GCP, RMSE 19cm

WorldView-1, Eritrea, 9 GCP, RMSE 23cm

Pleiades-1B, Eritrea, 74 GCP, RMSE 26cm

Pleiades-1B, Eritrea, 1 GCP, RMSE 28cm

Kompsat-3A, Eritrea, 11 GCP, RMSE 48cm

Kompsat-3A, Eritrea, 1 GCP, RMSE 53cm

ALOS PRISM, Eritrea, 3 GCP, RMSE 1.4m 

SPOT 7, Eritrea, 1 GCP, RMSE 1.4m

ALOS PRISM, Eritrea, 1 GCP, RMSE 2.4m 

 

If you would like more information on PhotoSat surveying you can visit the following links.

Satellite surveying

Mining Industry Applications

Oil and Gas Industry Applications

Case histories

Satellite survey of Libya with ground survey points

Are PhotoSat satellite surveys really more reliable than ground surveys?

By Gerry Mitchell, P.Geo, President PhotoSat

Satellite survey of Libya with ground survey points

World View 2 satellite survey in Libya with ground survey points for 3D oil and gas seismic survey.

 

In 2008, I would get a hollow feeling in the pit of my stomach whenever customers phoned or emailed to tell us that the PhotoSat surveys did not match their ground surveys. Back then, I was sure there was a problem with the satellite photos, or that we had made some terrible mistake in our processing.

However, by 2013 our customers were using PhotoSat satellite surveys to check and adjust their ground surveys.

Ground surveys right, PhotoSat surveys wrong?

Back in 2008 it was clear to everyone, including me, that ground survey data was right and satellite survey data wrong. After all, ground survey data was collected by someone who had stood on the ground. It was the “ground truth”.

In comparison, the PhotoSat surveys were produced from satellite photos taken from 750 kilometers above the earth. Of course the ground surveys were right and the satellite photo surveys were wrong. Or so we thought. As we did more and more satellite surveying projects, we began finding obvious ground survey errors. Some of these projects had thousands of ground survey points.

ground target at mining project drill hole

Ground target at a mining project drill hole with arms 20cm wide and 1m long. The image to the right show how this target appears on a 50cm ground resolution GeoEye satellite photo.

 

Some ground surveys wrong, PhotoSat right

We began finding projects with two sets of ground survey data, one set matching the PhotoSat surveying perfectly and the other set mismatching. Investigating these cases with customers was eye-opening and often entertaining.

On one project in southern Mexico, all of the ground survey points on or near roads matched the PhotoSat surveying perfectly. The points in remote areas, particularly on the tops of hills, had differences of two to five meters in elevation.

So what happened? The contract surveyor had used his high quality, bulky, GPS surveying equipment for the survey points that he could drive to. But he had sent his young assistant with a hiker’s GPS to all of the survey points on the hilltops. The surveyor was confident that the client would never check those remote points.

By 2010, we had become much more confident in the accuracy and reliability of our PhotoSat surveying. When there was a mismatch between PhotoSat surveying and ground GPS surveying we began suggesting that the PhotoSat surveying was “usually right”.  As you can well imagine, many of our customers, and all of their surveyors, were sure that I was delusional.

We had to find another strategy. We began saying, “Thanks for telling us about our mistake. Please send us a copy of your survey data and we will see if we can identify and fix our problem”.

Drill hole with 40cm by 40cm white concrete block

Drill hole with a 40cm by 40cm white concrete block on a mining project in central Mexico. The drill holes on this project were surveyed three times by three different GPS survey contractors. The coordinates of this drill hole on the three surveys are shown on an extreme zoom of the PhotoSat WorldView satellite survey. The PhotoSat survey has more reliable coordinates than any of the 3 GPS surveys.

 

Not all GPS surveys created equal

We also learned that not all ground GPS surveys are created equal. All good quality GPS systems record the GPS signals for later processing, so we began asking for copies of these GPS recordings along with the GPS ground survey coordinates.

The effect of this simple request on the quality of the survey data was remarkable. Some surveyors would immediately go and resurvey the ground points as soon as we asked for the GPS recordings.

By processing the GPS recordings we could see how long the surveyors had been at each point. In many of the significant mismatches, we discovered that the GPS recording times were much too short for ten centimeter accuracy. At first we had pushback from many surveyors when we suggested that their coordinates were probably inaccurate.

Then in June, 2011, the International Association of Oil and Gas producers published a thick report of guidelines for GPS surveying, freely available as a PDF file. For us this was a godsend.

Whenever there was debate about GPS accuracy, we would email a copy of the report saying, “These are the guidelines that we are relying on.  Please tell us where they are wrong”. All the discussions about recording times for GPS accuracy stopped.

Most ground surveys are good quality

Of course, it’s worth noting that most of the ground surveys that we receive are very good. Only occasionally are there serious problems that we cannot easily resolve. And of course PhotoSat also makes occasional processing errors and mistakes.

We always investigate whenever the PhotoSat surveying does not match the ground surveying. When we find it to be our mistake, we fix the PhotoSat survey data and resend it to the customer at no cost.

Correcting multiple mismatching ground surveys

By 2013, many of our repeat customers no longer assumed that the PhotoSat surveys were wrong when they did not match their ground surveys. In just five years there had been a 180 degree shift. In 2008, ground surveying always proved that PhotoSat surveying was wrong. By 2013 the PhotoSat surveying was being used to quality check and fix ground surveying.

This is great for projects with several different ground surveys. These are often surveyed by different contractors. For example, we have one case of an oil and gas project with five different ground GPS surveys performed by five different contractors. We proved that none of the ground surveys matched any of the other four ground surveys.

The key ground survey was for an oil well that discovered several hundred million barrels of oil. We matched the PhotoSat survey to the discovery well. All of the other four surveys mismatched the PhotoSat survey, each by different horizontal and vertical distances.

We used the PhotoSat survey to measure the offsets of each of the ground surveys from the oil well. Then we adjusted the other four surveys to match the oil well. This gave the project a consistent set of ground surveys all matched to the oil well.

This case history is described in more detail here.

Give GPS surveys on an oil and gas poject

Five GPS surveys on an oil and gas project. Each was done by a different survey contractor. None of the surveys matched each other. PhotoSat detected the mismatches and adjusted the survey data to produce a coherent survey data set.

 

Please see the experience section of the PhotoSat website for additional case histories and accuracy studies.

geologic formations in northern iraq

The accidental discovery of a new way to produce accurate elevation surveys from satellite photos

By Gerry Mitchell, P.Geo, President, PhotoSat

geologic formations in northern iraq

3D WorldView-2 image looking along dipping geologic formations in Northern Iraq. Produced by PhotoSat.

In an effort to find a faster way to produce elevation surveys from satellite photos, PhotoSat geophysicist Michael Ehling and I accidentally discovered a novel way to greatly improve the accuracy and resolution of satellite topographic survey results.

It was 2007, during the peak of the natural resource boom and PhotoSat could not keep up with the demand from Vancouver mining companies who needed accurate satellite survey data for their projects in remote parts of the globe. Without accurate ground surface surveys the mining engineers couldn’t produce reports of ore body volumes. Without the engineering reports the companies couldn’t report their mining discoveries to a booming stock market waiting expectantly for their news.

Interactive photogrammetric processes

Michael and I had been watching how photogrammeters produced elevation surveys from stereo satellite photos since 2004, when stereo IKONOS satellite photos first became available. PhotoSat was buying stereo IKONOS satellite photos from Space Imaging, now part of DigitalGlobe.

We were reformatting the photos so that the photogrammeters could produce elevation surveys using computer systems that had been designed for processing stereo photos taken from airplanes. They were using highly interactive processes and were taking an average of 150 hours to produce satellite surveys for 100 square kilometer projects.

Automatic matching

Michael and I could see that the processors spent most of their time interactively measuring the matches between identical features on pairs of satellite photos. The photos had been taken with the satellite looking at the same area on the ground from different directions. By identifying identical ground features on each of the photos, and precisely measuring their locations, the elevations of the features can be computed.

When Michael and I asked if the photo feature matching could be done automatically we were told that the automatic process usually didn’t work, but when it did, editing the results took more time than doing the matching interactively, so no one used it. As geophysicists we were intrigued by what looked like an interesting technical challenge.

Oil and gas seismic processing tool box

In the 1980’s and 90’s when I was working as a Geophysicist in oil and gas exploration I processed a lot of seismic data. Oil and gas seismic survey data is used to image geological formations thousands of meters below ground in the search for oil and gas. Seismic data processing has always been one of the most complex and computer intensive data processing fields, with expenditures of billions of dollars annually.

Over the past 50 years seismic processors have developed an immense array of data processing tools, including many automatic image matching tools, and I thought that we could probably apply these to the satellite photos.

Gerry and Michael at the siesmic workstation

Oil and Gas seismic processing and interpretation workstation. Gerry Mitchell on the left and Michael Ehling on the right. This technology was the inspiration for the PhotoSat satellite processing system.

Michael tested seismic processing image matching tools on stereo IKONOS satellite photos for several months in 2007. He had to format the digital satellite photos so that they would look like seismic data to the seismic processing systems, run tests, and then reformat the results to look like photos again.

We were in search of a faster way to produce the survey results that the photogrammeters were spending hundreds of hours to produce. We were testing with a pair of IKONOS satellite photos that had already been processed by the photogrammeters so that we could compare our results with theirs.

Gerry, Michael and Jayda at workstation

Michael, Jayda and Gerry using the PhotoSat Workstation on a satellite surveying project.

Initial PhotoSat processing test results were amazing

After three months of testing we had our first real success. We were astounded by the results. We could see many fine topographic details on our test data that were simply not visible at all in the photogrammetric processing.

We continued to refine the process over the next few months until we had produced satellite survey results that were over three times as accurate as the photogrammetric processing and had much more topographic detail. The initial process took over 100 hours of computer processing time to process 100 square kilometers, so we had not really found a faster way to produce the results, but completely unexpectedly, we had found a way to produce better results.

comparision of photosat survey

Satellite survey of a river valley processed by conventional photogrammetric methods on the left and by PhotoSat processing on the right. The PhotoSat surveying shows fine topographic detail on the river flood plain that has no expression on the conventional processing.

New PhotoSat Workstation built from scratch

Now, nine years after our initial accidental discovery we still have a team of researchers and software engineers improving our satellite processing system.

Several years ago they replaced the seismic processing system with a computer system built from scratch to efficiently apply the seismic algorithms and processes to satellite photos. This system, the PhotoSat Workstation, was designed to harness the processing power and speed of Graphics Processing Units (GPUs). The GPUs process numerical data a thousand times faster than CPUs. Older software that is retrofitted to use GPUs typically shows speed improvements of two to five times.

It took several years and several million dollars of software development, but since our initial discovery in 2007 we have successfully created an automatic process that produces satellite surveys much faster than the photogrammeters, with much higher accuracy and better topographic detail.

How can modern satellites photos possibly be accurate to 20 centimeters in 10 kilometers?

By Gerry Mitchell, P.Geo, President PhotoSat

ground control survey points in eritrea test area

3D WorldView-1 satellite view showing the ground survey points in PhotoSat’s Eritrea test area.

 

My intuition rebels at the notion that a satellite orbiting 750 kilometers above the earth, traveling at 7 kilometers per second, could possibly take photos of the ground accurate to 20 centimeters in 10 kilometers. When you take into consideration that these satellites have scanning cameras which take their photos like push brooms, with the north end of the photo taken a few milliseconds before or after the south end, and that the whole satellite is vibrating while the photos are taken, it boggles the mind. It just does not seem that such high accuracy should be possible. However, the satellite photos themselves, checked with tens of thousands of ground survey points, clearly demonstrate that the accuracy is real.

How do the satellites and cameras work?

We engineers and geoscientists in the commercial realm don’t actually know how these satellites and cameras work. Almost all of the technical details of the imaging satellites, their cameras, and their ground processing stations is classified. Or if it’s not classified it’s certainly very difficult to discover. I’ve had many conversations with satellite engineers who seem like they’d love to tell me why their satellites perform so amazingly well. Sadly, they simply aren’t allowed to discuss classified technology with anyone without the proper security clearances.

Whenever I have one of these conversations, it always seems to me that part of what the engineer knows is public and part is classified, but the engineer cannot be sure that he or she can remember what is still classified and what isn’t so it’s safest to say nothing. I’ve had satellite engineers decline to confirm information that is published on their own company’s website. Needless to say, this can make for some very awkward conversations.

We engineers and geoscientists in the commercial world only have access to the satellite photos themselves, and very general public information about the satellites and their cameras.

How accurate are the satellite photos?

When the Digital Globe WorldView-1 (WV1) satellite photos first became commercially available in 2008, PhotoSat acquired stereo photos for a test area in Eritrea where we have over 45,000 precisely surveyed ground points. When we shifted the WV1 photos 3m horizontally to match any survey point, we were amazed to discover that all of the survey points within 10km matched the satellite photos to within 20cm. We eventually documented this discovery in an accuracy study white paper that is now published on our website.

Now, eight years after that initial WorldView-1 accuracy study of the Eritrea test area, we have processed hundreds of satellite photos from the WorldView, Pleiades, SPOT and KOMPSAT satellites and have come to expect this incredible accuracy. I’m still in awe that this is possible and I still don’t know how it is achieved. I do know that the photos are amazingly accurate.

black and white photo of over 15000 ground survey points in PhotoSat Test Area

WorldView-1 satellite photo over the PhotoSat test area in Eritrea. The over 15,000 ground survey points used to confirm that the satellite photo accuracy is better than 20cm in 10km are shown as black dots. The completely black areas are survey points every 20m along lines separated by 100m.

 

 Colour image of a one meter PhotoSat survey grid produced from the WorldView-1 satellite photos

Colour image of a 1m PhotoSat survey grid produced from the WorldView-1 satellite photos. The ground survey points demonstrate that the PhotoSat grid is accurate to 35cm in elevation.

 

 

Tailings dyke elevation image number 2.

Monitoring Tailings Dykes with Satellite Elevation Data

In both the oil sands and mining industries, the integrity of tailings dykes is extremely important. Recent tailings incidents demonstrate this. Mapping the tailings dykes and beaches can be challenging with hazardous conditions restricting access for ground surveyors. Using satellite-based elevation mapping allows for data to be collected remotely, with no risk for ground personnel and no permits needed. Regular topographic mapping during construction allows the design engineers to confirm that the dykes are being built to design specifications.

Currently PhotoSat regularly surveys the topography of tailings dykes for the Alberta oil sands mines to an accuracy of 15cm in elevation. In fact, we map the entire tailings systems for Suncor’s Millennium and Steepbank mines about every two weeks. These surveys are used by a wide range of engineers and planners at Suncor. They even did a presentation about their experience comparing different survey options and why they settled on PhotoSat’s technology as their main topographic survey method.

Tailings dyke elevation image

Elevation image of a tailings dyke, December. Red is high, blue is low.

Tailings dyke elevation image number 2.

Elevation image of the same tailings dyke 6 months later. Red is high, blue is low.

Unique Methods for Elevation Mapping

Satellites can collect imagery anywhere in the world, and with new high resolution satellites being launched regularly, there are more options and collection times keep getting faster. Also, PhotoSat has a unique, automatic system for processing stereo satellite imagery to extract the bare-earth elevation values. That’s right – we invented this process ourselves here in Vancouver, and continuously improve the system to get better and better accuracy results. Additional information about the technology we use can be found on the Technology page. And we test our system regularly by publishing accuracy studies that are available on our website here.

We also survey all parts of tailings projects beyond the dykes for a complete profile of a mine site tailings area, including the sand dumps, tailings beaches, and mature fine tailings. The advantage of satellites is that they can collect imagery over a large area in one shot, providing an instantaneous snapshot of the entire tailings beach waterline, the geometry of the beaches, and the height of the tailings dykes. Areas from 100-200 sq km can be collected in one satellite pass.

Our standard elevation accuracy specs for mining projects is better than 30cm, and you can find out more about our digital elevation data package here. If even higher accuracy is required, contact us as we often can provide higher accuracies depending on the project.

To find out more about our engineering grade satellite topography, contact us at info@photosat.ca or 1-604-681-9770.

satellite photo of a tailings beach.

Improving Safety for Mine Survey Teams: How Ground Surveying Fits Seamlessly With Satellite Topography

Mine survey teams perform a job that’s increasingly vital, increasingly technological – and more dangerous every day. When they’re doing preliminary work to acquire geophysical data for exploratory purposes, or scouting out pit placement, they’re subject to dangers including rockfalls and environmental dangers that can include severe weather and wild animals. Many mine sites are in inaccessible locations, in rugged terrain far from habitation, where it’s hard to put teams and even harder to get them out again fast when someone gets hurt.

At the same time, the industry is expanding into new regions where mining has previously been carried out with pick and shovel or even literally by hand. In sometimes socially-volatile places where old mine workings don’t show up on maps that are often themselves inaccurate, mine survey teams are saving the lives of miners by supplying engineers with accurate data – but they’re endangering their own safety to do it.

And what about when ground survey teams visit a working open mine to check for bench integrity? They’re sharing their working environment with heavy trucks and putting themselves in the way of slumping bench walls and falling debris.

PhotoSat’s 30cm accuracy satellite topography can provide a solution by filling in part of the puzzle. Mine survey teams will always be needed, but their exposure to risk should be minimized. When you get your elevation data from LiDAR or GPS, it can be significantly slower than PhotoSat’s unique geophysical processing technology. You’ll typically wait weeks, especially for aerial LiDAR. PhotoSat usually provides a client with engineering quality elevation mapping within 5 days, and there’s no boots on the ground so safety risks are minimized.

That doesn’t mean ground survey teams, LiDAR or other scanning technologies are redundant. Just look here to see how one of our clients, Suncor, combines multiple scanning technologies to get the data they need.  In 2014, Suncor and PhotoSat presented on the benefits of incorporating satellite surveying into their survey process for their Tailings Reduction Operation (TRO). With many areas of the TRO cells inaccessible to ground surveyors, the satellite-based technology reduced exposure to hazards.

But it does mean there’s a way to get a fast, engineering quality mine survey that can be used for multiple engineering and planning applications – without putting anyone in harm’s way.

To find out more about PhotoSat’s 30cm accuracy satellite topography for mine surveys, contact us at info@photosat.ca or 604-681-9770.

satellite photo of a tailings beach.

High resolution satellite photo of a tailings beach.

elevation image of a tailings beach

PhotoSat elevation image of a tailings beach

A comparison of survey methods for Suncor’s oil sands mine

At the Trimble Dimensions conference in 2014 Suncor and PhotoSat presented the results of Suncor’s use of our satellite surveying for their Tailings Reduction Operation (TRO) at their oil sands mine in Northern Alberta. The mapping area is about 271 km2.

The full conference presentation PDF can be seen here.

suncor tailings areas

Suncor’s tailings: 50cm WorldView satellite photo                                         1m elevation image

 

In 2012, Suncor’s survey department was given the challenge to do monthly topographic surveys of all TRO cells. They tried surveying with GPS equipment, however less than 20% of the area was safely accessible by ground crews. Suncor also tried 3D scanners but found them very slow, requiring multiple set-ups and the data was sparse. They had previously tried airborne LiDAR but found the point clouds to be prohibitively large, and the data delivery to be frustratingly slow.

In 2013, the engineers at Suncor knew they were in need of a surveying method that would have high accuracy, fast delivery, and improve safety for field crews. PhotoSat stepped in to produce engineering quality elevation mapping from satellite photos quickly and safely. Stereo satellite photos were collected over the mine site, providing a snapshot of the entire site every two weeks. Highly accurate elevation data was then produced from the stereo photos using our unique geophysical processing technology.

We provided Suncor’s team with the satellite survey data within 5 days of the satellite photo acquisition to use at their biweekly planning meetings.

Elevation image differences

Elevation image: January 20                                                           Elevation image: February 23

Many features visible in the January 20 topography were buried by tailings by February 23.

Oil sands sand dump with contours

50cm tailings lift thickness contours: Jan 20 to Feb 23

 

During the presentation, Suncor also discussed the advantages of the customization available with our data. For example, PhotoSat provides Suncor with data in their local mine grid coordinate system. Also, we provided a ‘thinned’ version of the elevation grid, which reduces the density of point clouds in flat areas without degrading the quality and accuracy.

Taking all this into account, since 2013 Suncor has switched to satellite surveying as their main surveying method for their TRO Operation. We have been surveying this area about every 2 weeks since 2013, and continue to at the time of this post.

 

Suncor still uses GPS equipment for surveys of some areas of the mine, but for all the non accessible areas PhotoSat’s satellite mapping is the preferred method. The high resolution elevation data is also used for the tailings pond beaches, as well as mine pit advance and overburden dumps. One of the great features is that the satellite surveying is used by a variety of groups, including Tailings Engineers, Geotechs, and Production Planning.

For the full story, view or download the conference presentation PDF here.

In later posts we’ll look at how Suncor has adopted satellite surveying for mapping mature fine tailings cells, as well as mine site toes and crests.

If you have any questions feel free to contact us at 604-681-9770 or info@photosat.ca.