No, they would not be cheaper to off-load in Anchorage.  Anchorage doesn't have a deep enough port and so it is great for consumables, cars, (barges) etc.  But for heavy-duty, large capacity, long-haul ships, which are required to profit from raw resource delivery.  No freight would need to be trucked to Port MacKenzie.  Very little of the resource freight would need to be trucked anywhere besides the delivery point - Port MacKenzie.