Safe place to mine HQ items? Why, any mine where you Defend yourself. Effects vary, but the victory is sweet. Maybe staying together with other miners. All armed, perhaps meekly, but still.
-The pks... how much do you see them risk in the mines? Not exceedingly much, in general. Unless they happen to have the town and are camping the hell out of it [Looking at you, Broken Hills]. In which case, you shouldn't be at the town in the first place, and Gecko is a fairly good place second after that.
Key notes: Make friends. You aren't the only one to use the mine. There is safety in numbers, even more if armed.
Don't stick around: Always be moving, and try not to burn all your APs up on mining(meaning, let the APs regen after each swing); this tip matters most to the fighters who defend their right to mine.
Bring Boomsticks: If you're a pure crafter, hopefully there was a way to work crits into your build or some other method of combat (including pure evasion with hyped Sneak skill), otherwise you're just a defenseless wuss. If so, your pk problems require outside intervention of some sort, as you cannot be yourself a deterrent. You WILL be trampled at others leisure.
Lookout: You're only miners per se, but with simple lookouts (trying to have people near the spawns, or at corners), one may be able to save the majority, who can escape. Sometimes a sacrifice is worth it. You can always make more things, and respawn.
Defend yourself: Death will happen to the char. Try to make the pk share in it, however. Practice and some skill will enable this, even down to his bluesuit and a simple SMG, a char can be dangerous.