Twin Rivers Paper previously installed and ran a reject refining process in order to improve their pulp yield. However, once the process was implemented it decreased the cleanness in the produced pulp which is undesirable for customers therefore the process was shut down. Currently the rejected chips are either being burned or sent to landfill but the issue with this is that there are still good fibers within those rejects that are able to be pulped. The objective of this research is to implement a reject refining process at the mill that will recover the good fibers from the true rejects in order to increase the overall pulp yield, which is economically beneficial.