Drone-based Volume Measurement Delivers Big Time-Savings to Mining
Dallas VanZanten of Skymedia Northwest tells how he uses volume calculations for his clients and shares best practices
A few weeks ago, DroneDeploy announced the release of our new volume measurement tool, which allows users to instantly calculate accurate volumes on any map. Since then, many people have begun using the tool for a range of applications, including measuring stockpiles and extraction pits.
To help you learn more about how DroneDeploy’s volume tool can impact your business, we wanted to share some insights from one of our users.
With that in mind, we’d like to introduce Dallas VanZanten, owner of Skymedia Northwest, an aerial mapping and photography company, to tell how he uses volume measurements and share his tips for getting more accurate calculations.
Dallas started Skymedia Northwest two years ago. With 11 years of experience in the construction industry, and six years as an RC aircraft hobbyist, he saw a big opportunity for drones to bring value to the job site. Today, Dallas flies a DJI Phantom 3 Advanced, a Skywalk fixed-wing and a custom-built Pixhawk for construction, mining and manufacturing clients all over the United States. Dallas chose DroneDeploy because it’s “easy to use” and allows him to “spend more time flying and less time processing data.”
Monitoring Stockpile Inventory
One of Dallas’s clients is Granite Construction (NYSE: GVA), one of the largest civil contractors and construction materials producers in the United States. Dallas flies their production sites to help them monitor inventory of materials, including different types of gravel and recycled asphalt. Knowing the volumes of their stockpiles is vital information in Granite Construction’s decisions about whether to extract or process more material to fill their orders.
“They don’t want to spend too much money to process material that might sit for a while, but they also want enough so that when someone calls they’re ready to go” Dallas VanZanten
Although Dallas has flown multiple sites for Granite Construction, let’s focus on just one — a 30-acre site with a gravel pit and 7 stockpiles.
Why Use Drones?
It’s common to use traditional ground-based surveying methods to calculate stockpile volumes, but drones provide a huge benefit without sacrificing accuracy.
“Drones are safer, faster, and about half the cost as compared to traditional ground-based volumetrics.” — Dallas VanZanten
A ground-based surveyor would measure elevation every 5–10 feet on each pile. Not only would this take a lot of time and put the surveyor at risk climbing up and down the piles, but this process would also result in relatively few data points, compared to the digital surface area captured by a drone.
For this 30 acre site Dallas says “it would take a full day to cover with traditional methods.” How long was Dallas on site with his drone? Just thirty minutes.
Flying the Site
When he first shows up, Dallas goes through his safety checklist to checks for hazards that might affect his flight, such as power lines, high buildings or trees. He also notes wind speed and direction. When flying his DJI Phantom 3 Advanced, he plans his mission on the DroneDeploy mobile app and watches as the drone automatically takes off, follows the flight path and lands again. Once the flight is complete, he takes the SD card out of the drone and puts it into his laptop while still on-site for a quick image quality check..
Measuring Volume of Stockpiles
Once he’s uploaded his photos to DroneDeploy and his map has been generated, Dallas draws a polygon around the “toe” of each pile to define its base. The “toe” is where the slope of the pile meets the ground.
After that, he clicks the volume calculate button and the volume appears instantly. Behind the scenes, DroneDeploy’s algorithms calculate the volume cut and fill by measuring the volume between the baselayer of the pile and its surface. (To learn more about how volumes are calculated, check out our support documentation for the volume calculation tool and the elevation toolbox.)
Using DroneDeploy, Dallas has been able to achieve accuracy comparable to other tools, in a fraction of the time. For this site, all volume calculations were within 1% of alternatives, and “some of them were extremely close”.
In addition to sharing annotated maps showing volume calculations with his clients, Dallas also likes to share a 3D-model to help support his calculations.
3 Tips for Accurate Volume Measurements
Because of the way the volume is calculated, the elevations of the points selected when defining the base of the pile are very important. For example, accidentally selecting a point on a pile of rocks, as opposed to on the ground, will change the volume calculation and its accuracy.
To help him get highly accurate calculations, Dallas has a few best practices:
1.Use the Elevation View
“I always go to the elevation tool when I annotate because you can better tell where the toe of the pile is”, said Dallas. By seeing the elevation of the points he’s selecting, it’s easier to make sure he’s selecting points around the base of the pile.
Here is a volume calculation made while viewing the elevation layer of a map. Areas with the same color have the same elevation.
2. Visually inspect the piles on-site
“It’s important to know what piles they want calculated before you get to the site so that you can visually look at them on the ground”
“That way you can know if there are obstacles around them, indentions that might make an impact on the volumes so that you can bring that up with the client before,” said Dallas.
3. Know what a cubic yard looks like
He also recommends that “Anyone doing a volume calculation should educate themselves on what a cubic yard is (3ft x 3ft x 3ft)” and what it looks like, so that they can get a better sense of whether their calculations are “in the right ballpark”.
Want to talk to Dallas about volumetrics on your job site? You can reach him at [email protected].