Mining is not the most profitable endeavor in EVE. I think it’s an activity many of us measure in “fun/hour” rather than in ISK, but of course we like to be profitable, and mining can bring in quite a bit of money.
In fueling my obsession with spreadsheets, I’ve figured out that minerals are very often worth more per m³ than raw or compressed ore, in a lot of cases. That’s where the money is, in my experience.
From there it becomes a challenge of how quickly and efficiently you can mine. I’ve done as much as half a billion worth of minerals from moon ore in a single Covetor in a week, without fully maxed skills (though I’m close). I was in an alliance with someone who pulled a billion a month in a Venture.
If you’re pulling in more ISK than you spend in a given time period, then you’re ISK positive, or profitable. If you have fun, then you’re profitable with regard to the intangible. If you can find a steady income with mining to fuel the other things you want to do in the game, then you’re profitable.
Getting to those nine-digit numbers per day is largely a matter of skills, ships, fits, and fleets. Team up with an Orca or Porpoise, run an efficient mining barge, maybe do some multiboxing, and you could get to 100m a day–better if you’re in nullsec under the right conditions.
Of course, finding the right ores helps, too, and knowing where to sell your minerals once you’ve had them reprocessed can increase your gains substantially. Keeping on top of your cycles, alignment, boosts, and scanners can all help to make your mining more efficient.
I’ve found drones to also be an often underappreciated aspect of mining. Increasing drone efficiency has increased the amount of ore I can mine in a given time, enough that when I have four drones instead of five, I notice the difference.
I’m pretty sure the only way I’m going to get to 100m per day is to either mine with the intensity of a full-time job, or multibox with an alt. I personally don’t care for multiboxing, though it’s growing on me.