Otherwise wrote:
The good news is you could just sell the info. If the data is reliable and the deposit is rich enough there's probably companies around willing to jump through the bureaucratic and logistical hoops to get the project going, assuming you don't actually need an entire deposit's worth of platinum for shotguns. Maybe that's how ME cuts to the chase. Although even that much assumes quite a bit about the existence and status of other mining companies, the state of the market for platinum, whether or not anyone else has found this particular deposit before and decided that it was just too big of a hassle and whaddya mean you don't want realism in your video games?
A chance to explain away plotholes in the Mass Effect universe (and certain selected other universes - limited time only!)? This looks like something to finally get me to unlurk.
I'm pretty sure the info of the quantity and location of the deposit was the only thing of value in the games, and since Cerberus rarely works within the bounds of the law, I'd imagine they immediately sell off such information to the highest bidder in the black market, perhaps directly managed by EDI (the artifical intelligence on board Shephard's ship). If that were the case, then the visual feedback provided during the 'mining' minigame (seen in the comic by the graph in the corner) could very easily reflect the quantity you found
relative to the source's value on the black market. More importantly, it could (and probably would) reflect whether sources had already been reported through official channels, and thus are too risky to sell off if they've already been found. That is, you would get no blips and wouldn't appear to 'find' anything, even if there are metric kilotons of platinum, if EDI finds that such sources have already been found by others.
TL;DR - The fact that a highly advanced AI with immense connectivity and knowledge is acting as your visual awareness when mining can easily mean that said AI is only providing you with feedback for appropriately, and practically, profitable deposits.
Still doesn't explain why you can send probes to some planets, like Earth. I'm pretty sure there was some mention in Mass Effect lore about harvesting certain minerals prominent in Gas Giants though...