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References

Geocom

Quarry and mine site surveying
- Cristián Michell S. - Land Surveyor,

PROJECT PURPOSE

To demonstrate the Trimble UX5 and its applications to one of the largest mining companies in Chile, located at 4200 meters height. Chile has large mining sites located at 3000 meter onwards. Mining sites require quick and accurate surveying to monitor and measure ground terrain changes. The UX5 is a suitable mapping tool for such applications, not only for its versatility but also and most importantly for the accurate deliverables generated together with the Trimble Business Center Photogrammetry Module.

 

FIELD WORK

The work began with the flight planning to properly choose the area of interest, wind direction, flying height, overlap, flight time and pixel resolution. The area of interest chosen by the mining company was of a great importance, with one of the largest piles (80 m high), water supplying pools, accessing roads, and processing plants.

The flight was successfully executed, without a glitch:

  • Ground elevation: 4.200 MSL
  • Area of interest: 1 Km2 = 100 ha
  • Flights : 1 flight
  • Flight Height AGL: 200 m
  • Number of images: 420 images
  • Image overlap : 80%
  • Ground Sample distance: 6,4 cm
  • Number of lines: 14 lines
  • Distance between lines: 60 m
  • Flight Time: 27 minutes
  • Time and date: 17th January, 15:45 PM (local time)
  • Weather conditions: Partly cloudy, wind of approx 25 km/h
  • Control points: No control points were used

 

IMAGE PROCESSING

Data was processed using the Trimble Business Center Photogrammetry Module. With a straight-forward and fully automatic workflow, the simplicity and accuracy of this software suits the customer needs. TBC PM allows to generate high-resolution orthophotos and DSMs (digital surface model) with high level of detail. The workflow is completely automated and it can process thousands of aerial images at once.

During the processing, TBC automatically performs the Aerial Triangulation, adjusting the photo stations by identifying and matching tie points in the overlapping areas to correct the orientations and relative positions. Afterwards, and choosing a processing without GCP’s, the deliverables (3D colored point cloud, DSM and orthomosaic) were generated at medium resolution. The processing time was about 4 hours. The coordinate system used for the processing was Datum WGS 84, UTM, Zone 19 South.

 

APPLICATIONS

Multiple applications can be performed with TBC after the deliverable generation. Based on the mining company needs, the following analyses were done:

  • Contours generated at every meter
  • Volume calculation of the stock pile
  • Visual site inspection
  • Height pile monitoring
  • Profiling
  • Surface calculation and analysis
  • New road projections
  • Monitoring plants, pools and other mining facilities

 

DELIVERABLES


Image 1: Orthophoto with pixel resolution of 6,4 cm

 Image 2: Point Cloud with a density of 7.2 points/m2

Image 3: Contour Lines

 

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