why not make those broken picks ad give the npc an option to repair those broken ones?
and the broken ones should wight almost the same as the normal ones and dropping them should force you to do a little quest like "clean up the dirt evryone is throwing away - if you wanna mine again" or something like that.
(lke logging the picks one broke and only give you new ones when you brought the broken ones back to repair or sell)
and as for fishing, just do the same "clean up" idea if people throw stuff away
(wll i guss tis wod take too much of effort)