They don't expire until April 2020 so there is a "time premium" added. As the oppies get closer to the expiry date the time premium reduces.
Week 46 Wrap: Copper hits 2mth low as Trump threatens net zero pace; US rally fades; HotCopper’s picks
AN1 CuFe sells its Crossroads gold royalty to Northern Star for $4M cash; says better than waiting for mine launch