# Segregation Modeling in Stockpile Using Discrete Element Method
## 4 Segregation Results and Analysis  
The numerical simulation through the DEM includes stockpile loading and discharge. The live capacity is determined based on the difference between the total capacity and the mass drawn during discharge [22]. The main results are presented in Table 4. The particle shapes were modified in the last four tests. Tests 1 to 12 used sphere particles (S), test 13 used rounded cylinder particles (RC), test 14 used rounded polygon particles (RPg), test 15 used rounded polyhedrons (RPh), and test 16 used briquette particles (B).  
The repose and flow angles did not necessarily increase with different particle shapes when considering the same parameter calibrated using spheres. The sphere particles were well distributed in the stockpile, resulting in a high total and live capacity. In tests 7 to 12, the effect of increasing the number of fine particles was not clear, at least within the range studied. The ore recovery from the stock increased in cases with non-spherical particle shapes.  
Figure 4: Mean fragment size measured during stockpiling.  
Figure 3: Large-scale stockpile in the numerical model for validation. (**A**) Top view. (**B**) Profile view in the center of the stockpile.  
Figure 5 shows the visual particle distribution of the stockpile in tests 1 to 6, in which a coarse-to-fine particle ratio of 70/30% was modeled. The particle uniformity increased when lower feeding heights were used. Additionally, the segregation was less visible when the coefficient of uniformity was increased.  
Figure 6 shows the visual particle distribution of the stockpile in tests 7 to 12, in which a coarse-to-fine particle ratio of 60/40% was modeled. In these tests, the number of coarse particles around the stockpile visually decreased because the percentage of coarse particles in the system was decreased. Thus, the segregation was not clearly observed compared with previous results. In the last three tests shown in Figure 6 (CU = 3.5), segregation increased slightly.  
\begin{table}
\begin{tabular}{l l l l l l} \hline \hline
**Test** & \begin{tabular}{l} **Particle** \\ **Shape** \\ \end{tabular} & \begin{tabular}{l} **Repose Angle** \\ \({}^{\circ}\) \\ \end{tabular} & \begin{tabular}{l} **Flow Angle** \\ \({}^{\circ}\) \\ \end{tabular} & \
\begin{tabular}{l} **Total Capacity** \\ **t** \\ \end{tabular} &
\begin{tabular}{l} **Live Capacity** \\ **t** \\ \end{tabular} \\ \hline
1 & S & 31.06 & 44.53 & 0.325 & 23.50 \\
2 & S & 30.75 & 42.71 & 0.322 & 23.51 \\
3 & S & 30.24 & 41.95 & 0.321 & 23.93 \\
4 & S & 31.40 & 45.00 & 0.324 & 23.21 \\
5 & S & 30.61 & 44.05 & 0.322 & 23.43 \\
6 & S & 30.68 & 40.94 & 0.317 & 23.81 \\
7 & S & 31.32 & 44.88 & 0.324 & 23.30 \\
8 & S & 30.53 & 43.12 & 0.323 & 23.80 \\
9 & S & 30.10 & 42.85 & 0.321 & 23.86 \\
10 & S & 31.82 & 43.09 & 0.324 & 22.89 \\
11 & S & 30.46 & 43.01 & 0.322 & 23.64 \\
12 & S & 28.44 & 40.03 & 0.321 & 24.52 \\
13 & RC & 30.82 & 37.28 & 0.324 & 33.41 \\
14 & RPg & 31.17 & 38.63 & 0.324 & 35.58 \\
15 & RPh & 31.75 & 37.72 & 0.324 & 35.31 \\
16 & B & 29.59 & 29.26 & 0.324 & 34.71 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Numerical simulation of stockpile using the DEM.  
Figure 5: Different views of numerical stockpiles from tests 1 to 6. (**A**): Test 1, (**B**): Test 2, (**C**): Test 3, (**D**): Test 4, (**E**): Test 5, and (**F**): Test 6. (**i**) Top view, (**ii**) internal profile view in the center of the pile, and (**iii**) external profile view, respectively. Coarse particles in brown.