In today’s underground mass mining the ore pass is an important part of the infrastructure, since it connects two or more of the mine levels and used for conveying or storing large amounts of material. One of the main risks related to an ore pass is when operational or structural failure occurs thus leading to long-term loss of functionality. Developing or rehabilitating an ore pass when major failure has occurred is a time-consuming and expensive operation, and the risk of a long-term ore pass loss motivates the development of alternative transportation strategies in order to ensure the continuation of smooth operations in large underground systems. The study presented in this paper has been done at the Loussavaara Kiirunavaara AB (LKAB) Malmberget mine in Sweden, where the iron ore deposits are being extracted using sublevel caving. The study analyses the transportation system in one of the mine’s ore bodies using discrete event simulation (DES) with a focus on maintaining ore transportation in the event of the loss of an ore pass.