http://www.dem-solutions.com/support/files/examples/ResidenceTime.zip
This example uses custom particle properties. A simple rock-box contains particles which all have a custom property called Residence Time. The property measures how long the particle has existed in the simulation.

Please take a look at the code for your own project and remember to come back and post up any modifications or code snippets which will help other users along the way. Feel free to use this forum for asking questions about this contact model.
DEM Solutions Team.