Sibiu is right. See below from JVA. These provisions usually don't matter in practice, as it is the very existence of them that make the parties work collaboratively. CUU is not going to make an "offer" to Teck without knowing it can sell its interest in the market, and in all likelihod no third party buyer would have an interest in CUU's 25% share without having pre-negotiated with Teck on the terms of a future relationship - no sophisticated buyer would take the risk of Teck shelving the project or otherwise. So the provision exists to essentially force all interested parties to the table to hammer out the terms of a deal at the right time, and given the terms of the JVA and the nature of the parties, it is Teck who will be calling the shots on timing. We do not have leverage in a real way, because we know a third party buyer would not purchase our share without Teck being involved and essentially "blessing" it.  

23.3 Right of First Offer. Copper Fox will, prior to selling or disposing of all or any portion of its Interest, first offer to sell the Interest to Teck for cash consideration and upon such other terms and conditions as Copper Fox deems fit.