Well, clearly, RXL consider their prospects for the other metals...

Well, clearly, RXL consider their prospects for the other metals are better than for gold at Mt Fisher and so stand to gain funds from selling the gold resources identified to date that they can apply to their alternative exploration. At the same time, they will be retaining 30% in Helios and so still have an interest in Mt Fisher gold. Having said that, I commented earlier that companies usually farm out prospects to others while retaining an interest (which RXL previously did with DRM) and so it is curious why they have chosen to split it off into a new company and retain an interest in that company. One reason could be that they want the maximum funds that they can get up-front (ie ASAP), whereas farm-ins usually involve an initial payment for a percentage of the licence and a commitment for a specified level of expenditure on exploration. An additional percentage is often offered as an option after the first commitment is met, for a second level of expenditure on exploration.
As to why RXL want extra funds ASAP when they already have $11.5M, we will have to wait and find out from future announcements.