Measure Twice, Cut Once: The Importance of Satellite Surveying in Mine Site Planning and Construction

Oil sands elevation map with 50cm contours

Tailings elevation map with 50cm contours

Keeping a mine safe, profitable and compliant with legislation means frequent, accurate surveying. Planning begins with exploration and identification of likely sites, and particularly in oil and gas projects this can result in delays and false starts. Traditional methods of identifying potential sites suffer from major shortfalls, including the challenges of surveying large areas with traditional methods. The gap between geologists’ opinions and test drilling with a high likelihood of success has never been adequately filled, resulting in continuing requirements for multiple overlapping exploration techniques including exploratory drilling and ground-based surveying.

Mine site planning and construction has surveying needs that no other project matches. Like any engineering project mine site construction requires accurate surveying, but few other large engineering projects are built in hostile, difficult to reach terrain. And few others change so much or so fast. The fundamental fact about a mine is that it is dynamic – it alters the landscape and has to change itself too. That’s true of deep underground mining, open cast, leach mining and every other kind of mine operation.

Surveying Challenges

This presents surveying challenges. Mine sites are typically more remote than other engineering sites: the typical engineering project expands or connects to some built environment, while mines are usually in isolated places far from cities and infrastructure, meaning that they often require their own infrastructure. They’re often in rugged terrain too, or in climatic conditions that make surveying more difficult, such as the mountains of Argentina, the Australian outback, or the Arctic.

All of this means that mine surveying often can’t be done well with traditional tools. Even using modern on-the-ground tools like LiDAR and GPS, survey teams still need to travel to inhospitable terrain and map the site in weather that can range from uncomfortable to downright dangerous.

Then there’s the issue of changes to the mine site. While many of these occur underground in tunnel mines, even these produce significant amounts of waste rock. And larger open pit mines produce both overburden and (usually) tailings which must be monitored. Neither GPS nor LiDAR is usually fast enough to provide mine operators with monthly updates that allow monitoring and ongoing tailings planning and control. This is going to become a bigger issue over the next couple of years, post-Brazil.

So what about drones? Drone technology is in its infancy, so it’s likely to improve. Camera-carrying, real-time streaming drones are available to consumers for almost pocket-money prices; professional models can fly for hours and provide images of remote areas without risking human operators. Surely they can offer a solution?

Drones can do that. But they’re dependent on weather: just as much as larger aircraft, they can’t fly in high winds or see through clouds. They also require an on-site operator. Drones can do things a survey team can’t, like overflying tailings ponds, and they’re increasingly being offered as a solution to a mining industry that has more need for accurate, timely surveying than ever before – and less spare cash than before to spend on it. But they can’t provide the consistency and climate resistance that some mines require.

So far we’ve talked about surveying itself: gathering data. But the majority of data gathered, whether by ground or airborne LiDAR, GPS, drone overfly, or any other method, is just that: data, not information. Translating it into 3D models that resemble what’s happening on the ground and tells observers something they didn’t already know is a time-consuming, computer power-eating process. The acquisition and processing speeds, taken together, simply don’t match up to the pace of decision making that modern mining requires.

Satellite Surveying to the Rescue

All, that is, apart from satellite mapping. Satellites are unaffected by remoteness and inhospitable terrain. They’re definitely out of danger; whole mine sites can be imaged from space in one shot, including those areas where it would simply be impossible to send a survey team. And the accuracy of PhotoSat’s satellite elevation data is unparallelled: we deliver 30cm accuracy for mine site mapping, for instance.

More telling yet is the availability of the information. In contrast to processing times measured in weeks, PhotoSat uses a proprietary technology based on seismic survey data processing tools to drastically cut the time between data acquisition and final deliverables. For example, we map one of Suncor’s mine sites biweekly and deliver within just five days in order to meet their planning meeting deadlines.

PhotoSat’s proprietary image processing tech can be adapted to specific client needs too. For instance, our contract with Suncor involves using a mixture of high and low resolution elevation grids, depending on where the imagery is used and taken. We use high resolution data to map Suncor’s mature fine tailings pond, overburden dump, and mine pit advance to an accuracy of 15cm elevation or more. One result of this approach is that the same images can be used by multiple departments – PhotoSat derived images are passed along to Suncor’s Tailings Engineers, Geotechs and Production Planning departments.

Well sites in Alberta

Well sites in Alberta

During an unrelated project for producing SAGD well sites in Alberta, PhotoSat was able to identify 70 well sites, resulting in a total project cost of $12,000 – just $170 per well – during a project that lasted from initiation on January 30, 2015 through image acquisition on February 4th to processing completion on February 6, 2015. The accuracy of the well head locations we provided were within 11cm RMSE, as compared to Government of Alberta certified RTK surveying. We were able to provide 50cm contours and a 1m elevation grid over potential well pad areas without needing exploratory drilling, and without a single boot on the ground or drone in the air.

To learn more about PhotoSat’s revolutionary satellite topography system and what it can do for your business, contact us at info@photosat.ca or 604-681-9770.

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.

Case study: Reducing Suncor’s mature fine tailings inventory

This post is part 2 in a series looking at how Suncor uses our topographic survey data to  assist their Tailings Reduction Operation (TRO). In this post we’ll look at how they use the data to measure the thickness of their mature fine tailings (MFT) dewatering cells.

Background on mature fine tailings

Mature fine tailings are the clays from the bitumen ore that are suspended in the tailings water. To reduce the area and volume of oil sands tailings ponds, tailings water with suspended clay is mixed with a flocculent which causes the clay to settle out. The tailings water is pumped into dewatering cells where clear water drains off for reuse in bitumen processing while the clay is left behind.

PhotoSat has developed a process to measure the thickness of the clay in each of the mature fine tailings cells in thickness intervals of 15cm. We use our highly accurate topographic mapping between two satellite photo dates to create the detailed elevation maps.

Suncor’s MFT designated drying areas:

  • Total surface area 7.5M m2 (1,866 acres)
  • 697 tailings cells
  • 2788 discharge locations
Suncor mature fine tailings areas

Suncor mature fine tailings areas

 

Zoom of MFT designated drying areas

Zoom of MFT designated drying areas

 

How it works

In last week’s post, we saw that Suncor compared our satellite topographic surveys to other survey methods, and has switched to using PhotoSat mapping as their main surveying method for their TRO operation. The success of this service led PhotoSat, in collaboration with Suncor, to develop a process for automatically mapping the thickness of the mature fine tailings dewatering cells in increments of 15cm. This helps them reduce existing mature fine tailings inventory. The isopachs are provided in map (polygons) and tabular forms.

Satellite photo of MFT system 1

Satellite photo of MFT system 1, July 27, 2014                     Elevation image of MFT system 1, July 27, 2014

 

 

Isopachs (thickness) of MFT System 1

Isopachs (thickness) of MFT System 1, June 29 to July 13                  Thickness changes, July 13 to July 27

 

The spreadsheet data we provide also includes MFT volumes since the last pour, the total area in m2 covered by MFTs, the area of the polygons, the utilization of the polygons, and the MFT lift thickness.

Mature fine tailings mapping from our 15cm accuracy topographic surveys improves the monitoring and measurement of the tailings, providing Suncor with a cost-effective and reliable alternative to GPS surveying and aerial LiDAR mapping. Using satellites also reduces safety risks for field crews.

Next time we’ll look at how Suncor has adopted toes and crests mapping as part of their TRO process.

For more info on our topographic surveys contact us at info@photosat.ca.

 

 

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.