# Influence of Crushed Rock Properties on the Productivity of a Hydraulic Excavator
## 4 Results and Discussion
### Factors Influencing Excavator Productivity
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Source** & **Material** & **Fill Factor** & **Swell Factor** \\ \hline \multirow{8}{*}{[PERSON]} & Wet Earth, Loam, Sandy Clay Loam & 1.2 & 1.2–1.43 \\  & Natural Bed Clay, Damp Sand, Sand \& Clay, Lime Rock w/Fines & 1.1 & 1.05–1.33 \\  & Rock and Earth–25\%/75\%, Dry Clay, Dry Earth, Topsoil & 1.0 & 1.25–1.56 \\  & Rock and Earth–50\%/50\% & 0.95 & 1.29–1.38 \\  & Rock and Earth–75\%/25\% & 0.9 & 1.25–1.42 \\  & Dry Sand & 0.9 & 1.11–1.13 \\  & Broken limestone & 0.8 & 1.63–1.70 \\ \hline \multirow{8}{*}{Caterpillar} & Moist loam or sandy clay & 1.0–1.1 & 1.2–1.43 \\  & Sand and Gravel & 0.95–1.1 & 1.11–1.15 \\  & Hard, Tough Clay & 0.8–0.9 & 1.34–1.43 \\  & Rock—Well Blasted & 0.6–0.75 & 1.49 \\  & Rock—Poorly Blasted & 0.4–0.5 & 1.67–1.80 \\ \hline \multirow{8}{*}{Komatsu} & construction application & & \\  & Excavating natural ground of clayey soil, clay, or soft soil & 1.1–1.2 & 1.22–1.43 \\  & Excavating natural ground of soil such as sandy soil and dry soil & 1.0–1.1 & 1.25–1.46 \\  & Excavating natural ground of sandy soil with gravel & 0.8–0.9 & 1.18–1.41 \\  & Loading blacked rock & 0.7–0.8 & 1.49–1.80 \\ \hline \multirow{8}{*}{Volvo} & mining application & & \\  & Excavating natural ground of clayey soil, clay, or soft soil & 1.0 & 1.22–1.43 \\  & Excavating natural ground of soil such as sandy soil and dry soil & 0.95 & 1.25–1.46 \\  & Excavating natural ground of sandy soil with gravel, Loading & 0.9 & 1.18–1.80 \\  & blasted rock & & \\ \hline \multirow{8}{*}{Liebherr} & Earth/Sandy Clay & 1.0–1.1 & 1.2–1.375 \\  & Hard and Compacted Clay, Sand/Gravel & 0.95–1.1 & 1.11–1.43 \\  & Rock—well blasted & 0.75–0.95 & 1.49 \\  & Rock—averagedly blasted & 0.6–0.75 & 1.58 \\  & Rock—poorly blasted & 0.4–0.6 & 1.67–1.80 \\ \hline \multirow{8}{*}{Liebherr} & Clay and sticky material, clay, sandy loam, moist material & 1.1 & 1.1–1.43 \\  & Sand, sand gravel mixture, moist & 1.0–1.1 & 1.1–1.15 \\  & Hard dry clay & 0.9 & 1.24–1.43 \\ \cline{1-1}  & Rock, well blasted & 0.85 & 1.49 \\ \cline{1-1}  & Rock, poorly blasted & 0.6–0.7 & 1.67–1.8 \\ \cline{1-1}  & Rock, deteriorated, layered shale, not blasted & 0.5–0.7 & 1.33–1.79 \\ \cline{1-1}  & Underwater digging of sand, gravel \& sand-gravel mixtures & 0.85 & - \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Excavator bucket fill factor from manufacturer handbooks. increase in volume that may occur when a block of rock breaks up to form rubble or when a mass of soil is excavated. It is well known that the swell factor depends on the granulometric composition of the respective material, exactly the same as we stated for the bucket fill factor. If we compare the mean loosening factor for blasted rock materials from Table 3 (\(\text{k}_{\text{l}}=1.55\)) and the mean swell factor from Table 2 (\(\text{k}_{\text{s}}=1.5\)), they are evidently similar. The loosening factor for overburden material at quarry Zervanjska is the same as the swell factor (\(\text{k}_{\text{l}}=\text{k}_{\text{s}}=1.4\)). Figure 5 plots dependencies of fill factor on swell factor based on data shown in Table 2.  
Mean values are taken for range values of the bucket fill factor and swell factor. The coefficients of determination of Volvo's, Liebherr's, and Caterpillar's data on the bucket fill factors and corresponding swell factors (Figure 5) exhibit significant interconnection of these two parameters, as is the case with the correlation of all data whose coefficient of determination also exhibited a significant correlation (R\({}^{2}=0.6483\)). All trend lines showed a decreasing trend, i.e., with increased swell factors, fill factors decreased. Based  
Figure 5: Dependence of the bucket fill factor on the swell factor of the material.