Tau-23, Tau-29, Sigma-19, Leeds, Omega-11 (dead for many other reasons), Omicron Gamma, Hokkaido. These are some systems which I'm aware that once had the reputation of having mining operations and miners playing in them in the past.
Dublin, Munich, Nagano, Omega-3 and Omega-7, Sigma-59, and whatever systems in Gallia and Liberty where they have concentrated ores. These system mining activities are summed up to Pobs and on-call only miners dishing out the valuables on demand. No need for for miners loitering around doing their stuff, unattractive chances for a pirate to stumble upon any activity at random.
I think the only place that escapes this trend is Pennsylvania. Is it because of the rookies? Because of the ease of access to the equipment to mine?
I say it's because it's one of the few who can operate on it's local economy, being bought in the same system for a modest but not base price profit.
But "Hellium and Ores do not work by the same system, Hellium is for rookies" you argue. I know. Ores are designed for exports, to make it's profit a sort of quest that takes you 3 regions away.
What I come to suggest in this post (once again, I think) is to reactivate the mining fields with the non-ore mineables, that can be acquired and sold at bases in the region, becoming part of the local economy. Miners and roleplayers or this or that faction can try out a short route suitable to their role, and even focus their rp activity around it. In turn, pirates and unalwfuls can have greater chances of meeting said miners/merchants, without it being a high stakes encounter, or a dull powertrading trip that just begs the merchant to "be killed and be done with it".
Keep the ores as it is, return the former fields with mining back into activity, make necessary adjustments to markets based on the new venue of activity and profit.