## 4 Discussion  
In areas where mineral resources are extracted, the key issue is to quickly determine the quantities of extracted or exploitable mineral resources. An accurate estimation of deposit parameters requires taking into account three potential sources of uncertainty: (i) the physical properties of the material in the deposit, (ii) the measurement methodology along with the accuracy of the measuring equipment \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Attribute** & **Raw** & \multicolumn{3}{c}{**Thresholded DoD Estimate:**} \\ \hline Areal Metrics & & & & \% of AoI \\ Total Area of Surface Lowering (m\({}^{2}\)) & 13,595 & 91 & & 0.67\% \\ Total Area of Surface Raising (m\({}^{2}\)) & 13,376 & 13 & & 0.10\% \\ Total Area of Detectable Change (m\({}^{2}\)) & 26,971 & 104 & & 0.39\% \\ Total Area of Interest (m\({}^{2}\)) & 45,444 & NA & & NA \\ Total Volumetric Metrics & & & \(\pm\)Error Volume & \% Error \\ Total Volume of Surface Lowering (m\({}^{3}\)) & 32 & 20 & \(\pm\) 9 & 46\% \\ Total Volume of Surface Raising (m\({}^{3}\)) & 11 & 2 & \(\pm\) 1 & 56\% \\ Total Volume Difference (m\({}^{3}\)) & 43 & 22 & \(\pm\) 10 & 47\% \\ Total Net Volume Difference (m\({}^{3}\)) & \(-\)21 & \(-\)18 & \(\pm\) 9 & \(-\)52\% \\ Vertical Averages: & & & & \\ Average Depth of Surface Lowering (m) & 0.002 & 0.217 & 0.1000 & 46\% \\ Average Depth of Surface Raising (m) & 0.001 & 0.178 & 0.1000 & 56\% \\ Average Total Thickness of Difference (m) for Area of Interest & 0.002 & 0.001 & 0.0004 & 47\% \\ Average Net Thickness Difference (m) for Area of Interest & \(-\)0.001 & \(-\)0.001 & 0.0003 & \(-\)52\% \\ Percentages (by volume) & & & & \\ Percent Elevation Lowering & 75\% & 90\% & & \\ Percent Surface Raising & 25\% & 10\% & & \\ Percent Imbalance (departure from equilibrium) & \(-\)25\% & \(-\)40\% & & \\ Net to Total Volume Ratio & \(-\)49\% & \(-\)80\% & & \\ \hline \hline \end{tabular} NA = not available.  
\end{table} 
Table 4: Changes in physical parameters of the Area of Interest in July 2013 calculated volumetrically with reference to the total volume of the gravel-cobble material’s net change recorded by the DoD (both lowering and raising) from the manually cleaned-up (new) to the CSF-filtered (old) DTM. The uncertainty analysis was calculated by simply using the minimum level of detection (minLoD) approach while accounting for a uniform error of 0.1 m.  
Figure 6: DEM of difference (DoD) for the AoI (August 2013 with MinLoD = 0.1). Hillshade map is shown behind the DoD for context. Description of the bars in the diagram: (A) Average Depth of Lowering; (B) Average Depth of Raising; (C) Average Total Thickness Difference. and also the measurement methods in the case of modern remote sensing (iii) the methods for classifying ground points as well as the interpolation of the ground surface and their respective analysis. In this context, a significant part of the research is focused on estimating the cubature or bulk density of the raw material under in situ conditions, all of the while using conventional and modern remote sensing methods such as digital close-range photogrammetry (structure from motion (SfM) photogrammetry) and terrestrial laser scanning. These works usually document relatively small (about 5%) differences between the parameters determined in a laboratory and those under field conditions by TLS [12]. This is all the more so because during the extraction or movement of the sediment resulting from natural processes (landslides, mud and rubble run-off, debris flow, etc. ), the cohesion and loosening of the sediment structure is reduced. As a result, it is often found that the volume of the deposited material is larger than that of the erosion niche. [PERSON] and [PERSON] [35] highlighted an average 7% prevalence of deposited volumes over the detected eroded volumes for two debris flow events in the Halltal (Austrian Alps).