As you noticed, every HQ miner is a prey animal, and it's hard to gather up HQ, since the mines are mostly dominated by strong gangs.
It's pretty frustrating to mine for ammo - however, you can get guns for high amount of low-tier craft, but nobody in sane mind would sell high-tier-ammo.
But i heard someone saying "come mining armed!". Yeah, as a walking loot.
Of course, there's always raids on mines by challengers.
However, in a time a challenging PvP fraction gather up the necessary materials, a currently dominating fraction would mine a tenfold amount of mats, enough to fight off and strike back, without thinking on material losses. They gather power like a snowball.
Support the strong, bring down the weak.
That's the current slogan of gameplay in FOnline.
There must be more challenge to the King of the Broken Hill.
Thereby, i suggest adding a second, more expensive type of private mine.
This one should carry a quickly depleting amount of HQ materials, just enough to provide materials to equip a few raids.
Then, it would be possible to craft enough equipment to state the operation start "tomorrow", instead of "(maybe) in two weeks, when we have enough mats".
It's a question of gang member motivation.