I think the advantage of only being listed in one exchange (ASX...

I think the advantage of only being listed in one exchange (ASX in this case), is that there is less expense to the company and less paperwork to file, reducing admin expense. During the bear market this is a no brainer way of keeping your company lean and reducing yearly expenses. Also, because of such little investor interest in uranium during the bear market, the advantages of a dual listing would be highly muted.

In a bull market however, the cost of additional listings is less important and the upside is far greater. Getting listed on multiple exchanges and bigger exchanges such as the NYSE and TSX improves your stocks liquidity, increases the pool of potential investors that have access to buy your stock and also promotes your company. All of this reduces your overall cost of capital and increases the chance that you are trading at a higher valuation.

I think it is paramount that Deep Yellow dual lists on the TSX and I am sure that a TSX dual listing already in the works, as the increase in admin cost will be paid back many times over by the benefits in increasing liquidity/investor pool and cost of capital.