It’ll come as no surprise, but stockpile volume measurement is one of the most frequent use cases for drones on worksites. Today, we’re giving you an in-depth look at how to use the Propeller Platform to streamline volume measurements and calculations, from quarries to mines and every construction site in between.
But first, let’s take a look at how more accurate stockpile volume measurements can impact your operations.
Why accurate stockpile volume measurement matters
With drone surveying and data processing and visualization software, you can count on exact stockpile measurements and get volume updates more frequently than ever before. This improved accuracy enables teams to tighten up worksite operations, from financial forecasting to supply-chain management to accurate reconciliation.
1. Prepare more accurate financial forecasts
Drones are less costly and easier to use than traditional surveying equipment—and far more accurate than “eyeballing” stockpile volumes. They put the power of frequent surveying in your hands and accurate stockpile volume data at your fingertips.
Having accurate inventory numbers every month means drastically reducing future write-offs, saving everyone on site money and boosting mine or quarry efficiency. Using drone surveying, “fluff factors” in inventory management have become a thing of the past.
2. Tighten up your supply chain
Knowing what you actually have on site also allows you to tighten up supply-chain management. Stockpile volume measurement reports give quick asset snapshots, from when you need more stock to how much is needed. If you are your own supplier, easily plan out when you need to start drilling and blasting. If an external supplier is used, you can plan out purchases and calculate a more accurate budget.
3. Reduce costly write-offs
All quarries need accurate information on stockyard tonnage to fulfill work orders and be financially solvent. But too often, big write-offs have been par for the course. Even when outrageously high, they’re an accepted status quo. Drone surveying and data processing software allow you to take volume measurements of your own stocks, and therefore, make slight adjustments each month to mitigate the mandated six-month check.
4. Plan with confidence with reliable stockyard volumes
As we’ve seen, the Propeller Platform lets you see the status of your quarry in minutes and measure stockpile volumes with a few clicks. Using sophisticated built-in volume calculators, you can quickly find tonnage values for your stockyard and make sure everything lines up with the amounts given by subcontractors.
For example, say you want to calculate the tonnage of a particular stockpile. Simply click around the base with your mouse. Propeller then measures the toe of that pile and calculates the volume. If you know the density of that material, simply enter it in the calculator to reveal the tonnage in seconds.
Additionally, Propeller can calculate actual dollar values of your piles—or the money sitting in the whole stockyard. See the value of inventory with every single stockpile report.
How stockpile volume measurement works in photogrammetry
How do drones and software actually measure stockpile volume? To answer this question, let’s take a look at some examples showing how Propeller’s different types of stockpile volume measurements work.
Ideally, a stockpile would be a shape with an easy volume to calculate, like a perfect cube or cone. But most of the time, stockpiles are irregular. Drone surveying captures irregularities and accurately renders them in your survey, thus allowing the computer to calculate the true volume of the shape, not a rough approximation.
This accuracy starts with the imagery. Drone photos capture significantly more detail than shooting points with a rover. Photos let you see the physical details between the individual points.
Both horizontally and vertically (Z values), drones are able to capture and render higher resolution data that’s just as accurate as traditional surveying. Correctly used, drones in conjunction with ground control can produce survey-grade accurate 3D surveys.
After you’ve flown your drone and photographed the quarry, that’s where a processing platform like Propeller comes in. Accessed from the browser on your device, the Propeller Platform uses drone photogrammetry methods and data processing software to stitch the images together. This involves pinning the images to the ground control positions, getting powerful machines and data experts to digest all the raw photos, finding overlaps and common points in images, and making a 3D reconstruction of the terrain.
Thanks to ground control points (GCPs), like our AeroPoints, and a known coordinate system (local calibration or otherwise), your data is accurate. This means you can measure right off the visual representation on your browser. Know your site’s progress and productivity in a few clicks by reviewing the timeline and checking the 3D site survey against design.
The type of measurements required vary on what information you need. From comparing the changes in a stockpile from one survey to the next to calculating volume from a reference level, you need to know when to apply which measurement type.
How to select the right volume measurement type for your stockpile
Once you’ve conducted a drone survey, it’s time to measure the volume of your stockpiles using the stockpile data. When it comes down to it, processing platforms like Propeller make this traditionally labor-intensive task simple and painless.
First, log into your Propeller portal and navigate to an area on your site where you want to measure stockpile volume. Before you start measuring stockpile volume, note that there are different types of stockpiles—from ramp- to bin-style to regular—and they need to be measured accordingly. Considering that, here are a few examples of the different ways you can measure volumes.
- Measure volume from a reference level. Set the baseline to a desired figure and calculate your total volume from that level up.
- Measure using a smart volume, and let the computer do the work. For a smart volume, the platform is extrapolating where the base of your pile is and giving you a total volume from there.
- Compare volumes between two surfaces. This could be survey to survey in order to see change and progress over time, or measure against a design surface to see how far you have left to go.
And because these volumes are accurate, you can enter in a known material density into the stockpile volume calculator to get the tonnage for any stockpile.
Let’s say, for example, you want to find how much material has been added or removed to a stockpile since your last drone survey.
Simply select the Polygon tool and draw a line around the base of the stockpile. In an instant, Propeller will “take” the thousands of recorded height samples within the boundary of this polygon. Conceptually, this is similar to a surveyor climbing across a stockpile taking thousands of elevation points—though clearly much safer.
Next, Propeller compares these height readings (from your current survey dataset) to those from your previous survey (at exactly the same horizontal locations). Volume changes are expressed as either positive change, where material has been added (labeled Fill) or negative change, where material has been removed (labeled Cut).
You can also see the “net” change (Fill + Cut).
It’s also possible to view changes in stockpile volumes as a cross section. In this case, Propeller reads the recorded height samples from various distinct datasets along a line that have been drawn, and renders the results on an interactive chart.
For stockpile measurement accuracy tips and tricks, read about best practices for stockpile volume measurements using the Propeller Platform.
How to measure stockpile volumes
The aggregates and mining industries are all about quantities—from how much is sitting in your stockyard to how much is going in your crusher or mill to how much you need to extract. Cut and fill volumes are used in almost every stage of the quarrying and mining processes, and while any calculation errors are a problem, these have the potential to carry over and affect your business in myriad ways.
Similarly, understanding quick pit and stockyard volumes takes the guesswork out of tonnage measurements, and thus the value of your stockyard. Using the Propeller Platform’s volume calculators, these measurements are quick and simple to complete.
First, fly your drone to capture site data
Before you can take a single volume measurement, you need to fly your drone to capture site data. There are a few ways to do this. “Drone surveying,” at its core, means using a drone to take aerial photos of your site and some form of GPS and ground control to tie the images down.
With recent technological advancements, there are two major workflows to get the job done: GCP-based drone surveying and PPK drone surveying. (Learn more about the difference between the workflows here.)
Next, let the Propeller Platform do the work
Once you’ve got the imagery you need, send it to Propeller for processing. Twenty-four hours later, your survey is rendered and you can begin measuring stockpile volumes in a few clicks and measuring road grades with an easy-to-understand colorized slope map. To get a better idea of overall progress, just upload your design surface and compare with the 3D survey, right in your browser.
You can also use drone-captured data for elevation surveys of blast areas. Whether you’re flying your whole site regularly or are specifically targeting areas for preblast planning, you can use the 3D survey to accurately calculate levels in just a few clicks. And, if you have any design or linework, overlay that into the model to help with accuracy and quality—and make sure you’re not leaving resources in the ground, a.k.a money on the table.
Let’s take a more in-depth look at how to measure stockpile volumes, first for quarries and mines, then for pits and stockyards.
How to measure stockpile volume for quarries or mines
Since these two industries have similar workflows, we’re going to explore how drone surveying can streamline cut/fill calculations for both. To see where cut and fill software can improve mine and quarry management and efficiency, let’s follow the material from extraction to the stockyard.
Visualize your blasts with 3D blast planning
Before you can build up your stock, you need to extract it. Making decisions with the most up-to-date and reliable information is critical for any site manager, especially when planning and executing blasting work on a mine or quarry site. Keeping your site survey and bench level plans updated and accurate can dramatically improve blast results and significantly reduce drilling and blasting costs.
Any area of interest on your mine or quarry can be easily and inexpensively surveyed with drones. Once your drone-captured photos are uploaded to a platform like Propeller, you can generate centimeter-accurate 3D models and georeferenced orthophotos of the blast area for further measurement and analysis.
When planning blast works to fill a specific customer’s order, a volume can be easily identified on the 3D model using the Volume to Reference Level measurement tool. You simply draw a shape around the blast area, set the bench level to “blast to,” and the computer crunches the numbers.
These images also provide a good source of data for visual assessment of blast results like muckpile shape, back damage, distribution, and fragmentation. Plan your postblast logistics using the fragments’ size and location data. You can also measure pile volume, fragment size, add annotations, and share blast reports with the stakeholders directly from the Platform.
With the Volume Compare feature, the blasted volume can be compared against the plan to ensure the right amount of material was extracted. If you have any design or linework, you can overlay that into the model to help with accuracy and quality—and ensure you’re not leaving resources in the ground.
How to measure pit and stockyard volumes
The measurement process for pit and stockyard volumes is similar to that of quarries and mines. However, having the correct grade blends going through your mill or crusher is essential to your measurement success.
Too often, insufficient input grades are only discovered after the fact, when the final material doesn’t add up to what entered the processing plant. Instead of backtracking, Propeller can be used to monitor your stockpiles before something goes wrong.
We know waste dump surveys can be difficult, too. It’s nearly impossible to send someone out to walk those piles. Drone surveying can capture the data you need in hours, not days, without sending someone to walk over dangerous piles.
No matter what area of site is surveyed, Propeller can process data within 24 hours—renderings, reports and all.
How to report on your stockpile volume measurements
We’ve written about tools and methods of stockpile volume measurement and how it works, but once you have worksite numbers in hand, what happens next? You need to be able to generate stockpile reports.
A step-by-step to generating stockpile reports using propeller
- Draw a polygon around the stockpile in question, double-click, and choose which kind of volume measurement you want.
- Next, navigate to the top right-hand menu and click on Reports.
- Choose either PDF or CSV.
- Click Download Full Report.
The data that appears on stockpile reports can be easily customized. After you click Download Full Report, simply use the check boxes in the Report Settings sidebar to add or eliminate data sets.
Share your volume reports
Sharing stockpile reports should be as simple as generating stockpile reports. With the Propeller Platform, it’s just that. Check out How to Create and Share Stockpile Reports with Propeller for a step-by-step guide to sharing your stockpile volume measurement data.