Quantity monitoring in mining environments is a challenge that can be simplified by using frequent drone surveys. By combining drone surveys, mine managers can obtain additional insight into the quantities available. This allows for better decisions on future mine work. However, the drone data has to be efficiently analyzed to be useful for mine monitoring. This article demonstrates how to use individual drone surveys over a mining site to track progress over time. Virtual Surveyor helps you to quickly do this with quantity reports and Cut/Fill maps.
- Create and organize your Terrain states.
- Clean terrains.
- Draw a boundary.
- Create a Cut/Fill map.
- Analyze Cut/Fill map.
- Export results.
Terrain State management
To deal with multiple drone surveys over time you need to use the Terrain State functionality. Create a Terrain State for each date the mine has been flown. Each drone survey data package (DSM and orthophoto) should be imported in the corresponding Terrain State. Switch from one terrain state to another using the drop down menu.
Drone data coming from mining operations commonly have many machines (bulldozers, excavators, dump trucks, etc.). You should not include these machines into your calculations. To clean your terrain, you can use the Remove Object tool or the Replace Terrain tool. To help you detect objects that need to be removed, you can also use the Slope Steepness Terrain Lens. This must be done for each drone survey package.
Select the operation area
Mines are typically quite large. Nevertheless weekly or monthly operations can be localized on a specific area. Many times the drone surveys cover the whole mine. You need to determine the area where you want to calculate your quantity changes. For example, you may focus on blasting areas or excavation zones. Use the boundary drawing tool to trace the limits of the area of interest.
This boundary is required for Cut/Fill analysis. If you want to generate an analysis over the whole mine, create a boundary over the entire area.
You can also use multiple boundaries localized to different parts of the mine.
Use the Terrain State manager to switch to the previous drone survey. Select the boundary and go to the TOOLS tab. In the Volume group set the most recent drone survey as reference for the Cut/Fill calculation within the Reference State box. Click on the Volume Difference button to launch the calculation. Cut areas appear in warm colors (yellow to red) and fill areas appear in cool colors (cyan to blue). Cut/Fill values for the entire area are available in the volume box.
If you have multiple areas of interest, you can select all the boundaries (by holding Ctrl on your keyboard). Cut/Fill calculations are run in parallel, but each area has dedicated map and quantity result.
Now that the Cut/Fill map is available, let's make it better and easier to analyze. Select your Cut/Fill map within the viewport or through the project view to get access to SELECTION - TOOLS for Volume. First, set the Min. Cut/Fill value to highlight only significant operation areas. Using a 0.3ft (10cm) value typically clears noisy areas. Then, reduce the stretch value a little to enhance the color appearance.
It is possible to focus the analysis on one cut or fill area to get quantity result for that specific area. Select the Cut/Fill map to get access to the Tool tab and activate the Extract Cut/Fill area tool. Click on the wanted area. A new volume item is created and if selected, related quantities display in the volume box.
If you need to deliver quantity report, you can export Cut/Fills analysis results and use these in third party software to layout a detailed report. Volume info can be exported as .csv to fill a spreadsheet or as .shp to draw a map. Activate all the volume items you want to export within the project view and go to the EXPORT tab. In the Volume group select the export format and click on Export Volume.
The volume box also contains a copy icon to copy the information directly to the clipboard.
Here is a sample report laid out with Microsoft Excel using the volume information from clipboard and a viewport screenshot.
It's also possible to export what you see in the boundary as a localized image. Activate all the items you want to export within the project view, select a boundary and go to the EXPORT tab. In the Terrain group select the export format and click on Export Image.