I can assure you that Canada works very closely with the United States and with Mexico across the full range of trade issues, including on critical sectors such as the aluminum sector. I have not heard any concerns expressed with respect to the transshipment of Mexican aluminum into the Canadian market, which seemed to be the situation implied by your question. If I've misunderstood, perhaps you could reframe it.
If the concern is the nature of Mexican aluminum imports from the world, there are a multitude of fora, committees, working groups and opportunities created by the Canada-U.S.-Mexico agreement for the three parties to have constructive discussions about that. However, as far as I am aware, no concerns have been raised with me or my team regarding the possibility of transshipment of aluminum through Mexico to Canada.