At 90 fishing you can fish rocktail which sell for 3k ea at the moment and you can fish around 100 per hour. (More or less depending on fishing level.) That means you make 300k+ an hour not deducting cost of living minerals.
At 94 cooking with cooking gauntlets you will no longer burn rocktail. Cooked rocktail can go for about 3.5k each. With a little extra effort you can gain some cooking exp and an extra 500 gp per rocktail.
Living minerals currently run at about 220 each so buying these you are still making around 280k+ an hour.
You could also kill living rock creatures which are levels 120 and 140 respectively and mine the minerals yourself if you have 73 mining. You receive 8 - 25 minerals per creature that you kill so you get around 800 - 1k minerals an hour at a high combat level.