Document Type

Conference Paper

Publication Date


Publication Details

A. McQuillan, Comparison of photogrammetry and survey laser scanning output data for use in mapping joints in open cut highwalls, 13th Coal Operators' Conference, University of Wollongong, The Australasian Institute of Mining and Metallurgy & Mine Managers Association of Australia, 2013, 347-354.


The Anglo American open-cut coal mines in Australia routinely obtain structural data from exposed highwalls to determine the potential for instability caused by joint orientation, joint dip, and joint persistence. Three methods are currently available to obtain this data: direct in-pit measurements with a geological compass, photogrammetry, and laser scanning. Direct measurements are often very time-consuming and can lack the precision of other methods due to the inability to perform proper line surveys where mandatory safety stand-off distances are enforced at the toe of each highwall. For this reason, photogrammetry has been the method of choice for many years, where stereo pairs are used to create a 3D image of the highwall. In recent years however, laser scanners now appear to be the preferred method of data acquisition due to their faster capturing and processing time, as well as their user-friendly CAD processing functionality. Concerns however have been raised over the accuracy of laser scanner data as examples to date have lacked the point cloud density necessary for picking representative joint planes. To resolve this issue, both methods were applied on the same highwall and the outputs compared. From this comparison, it was concluded that accuracy is not compromised with laser scanner acquisition methods as long as the correct intensity is selected prior to capturing the scan. Discrepancies were however identified between the joint orientation outputs of Sirovision and I-site mapping technologies. These discrepancies are attributed to the different algorithms each program uses, as well as the survey control and density of data points produced and required by each method.