My most recent strategy has been to create EHSP from the shiny chunks I've been mining. There's something like a 500 currant gain when you make EHSP out of the chunks rather than selling the chunks on their own. However, doing so requires extra money for energy and I think that might negate the extra currants gained. Further, making the EHSP requires either extra time gathering Flaming Humbabas or extra energy, and I think in that time you could mine more chunks of rock which would probably get you extra gems. On the other hand, if you make a substantial investment in energy/humbabas early on I can see this becoming a non-issue.
What do you think?