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 3d elevation image

Comparison to LiDAR verifies accuracy of WorldView-3 satellite elevation mapping to within 15cm

Back in March this year, we were proud to announce that we’d verified the accuracy of DigitalGlobe’s WorldView-3 (WV3) satellite topography. The digital terrain model PhotoSat produced from DigitalGlobe’s WorldView-3 stereo satellite data was found to be accurate to within 15cm in elevation. Of course, that meant our customers could look forward to unprecedented accuracy from us, with an accuracy study to back it up. Here’s the original piece from PRNewswire:

 3d elevation image

PhotoSat 3d elevation image from WorldView-3 satellite data of the Garlock Fault in California

Engineers to benefit from high quality elevation products

VANCOUVER, March 25, 2015 /PRNewswire/ – PhotoSat is pleased to announce that the elevation data processed from DigitalGlobe’s new 30 centimeter resolution satellite, WorldView-3, has been verified as accurate to within 15 centimeters. DigitalGlobe is a leading global provider of commercial high-resolution earth imagery products and services, and is the first company to offer 30 cm resolution satellite imagery commercially.

For the study, PhotoSat produced a 50 cm grid of elevations using its proprietary geophysical processing technology with stereo satellite images taken by WorldView-3. The resulting elevations were then compared to a 50 cm LiDAR elevation grid in Southeast California, accurate to approximately 5 cm in elevation and available on the OpenTopography website. The size of the comparison area was 88 square kilometers. The resulting 15 cm RMSE elevation accuracy was impressively achieved using a single ground reference point. The full WorldView-3 accuracy study is available on the PhotoSat website at www.photosat.ca/pdf/garlock-30cm-wv3-elevation-accuracy-report-mar2015.pdf.

PhotoSat’s highly accurate elevation grids have been used for years by oil and gas and mining engineers as a cost-effective alternative to ground surveying and airborne LiDAR mapping. The satellite imagery from WorldView-3 will allow PhotoSat to deliver the highest quality topographic data yet.

“The DigitalGlobe WorldView-3 satellite data is the highest quality satellite photo data that PhotoSat has ever processed,” said Gerry Mitchell, President of PhotoSat. “In this test, an elevation grid extracted from stereo WorldView-3 satellite photos matches a highly accurate LiDAR elevation grid to better than 15 cm in elevation. This result takes satellite elevation mapping into the engineering design and construction markets and directly competes with LiDAR and high resolution air photo mapping for applications like flood plain monitoring.”

“The fact that PhotoSat has validated our elevation data to within 15 cm is amazing and even exceeds our initial expectations,” saidKenyon Waugh, DigitalGlobe’s senior director of vertical segment products. “With these elevation products, customers in the oil, gas, and mining sectors can leverage our truly global reach and realize cost savings on the order of 50 percent.”

LiDAR and satellite elevation data

LiDAR grid compared to PhotoSat’s WV3 grid. Comparison of the LiDAR and WV3 elevation grids for a 1000m wide area. Minor differences between the elevation grids are visible.

 

About PhotoSat

PhotoSat has invented a new technology that generates the world’s most accurate satellite topographic mapping.  This engineering quality data shortens timelines and eliminates surveying delays in all phases of resource and engineering projects. We have delivered over 500 highly accurate elevation mapping projects, and have published a number of accuracy studies which are available on our website. For more information please visit www.photosat.ca.

About DigitalGlobe

DigitalGlobe is a leading provider of commercial high-resolution earth observation and advanced geospatial solutions that help decision makers better understand our changing planet in order to save lives, resources and time. Sourced from the world’s leading constellation, our imagery solutions deliver unmatched coverage and capacity to meet our customers’ most demanding mission requirements. For more information, visit www.digitalglobe.com.

To find out more, either visit us at  www.photosat.ca, view the original accuracy report here or contact us at info@photosat.ca.