2 months back, I found a nice Platinum hotspot (in an inner metallic ring) about 6500 LY out from Sol. I worked it for about a 3 to 4 weeks
In my T9 laser miner, I could fill up (576 tons) of Platinum, Osmium, Gold, Palladium and Monazite (from highest concentration to lowest) in about 2 to 2.5 hours. I did that until I had over 4000 platinum in the carrier (about 9 or 10 mining trips total switching off with exploration and exobiology after every two or three mining trips) and then went back to the bubble to sell it.
The platinum alone was worth about 1.4 Bil. I ended up giving a combined 750 tons of Platinum and Palladium to a friend just to get it off my carrier...by that time I was sick of hauling...I also paid him 200% of galactic average to fill my Tritium buy order, threw another billion into the carrier account and kept almost a billion to have on hand in my personal account, which is about where it was before I started selling stuff.