Although I am relatively inexperienced in this game and my knowledge banks are not yet that deep I have gathered, over my time doing both the industry side and the ganking side of my game, that highsec is not the place to be for miners. It's kind of a weird idea to understand but I believe you are less likely to lose your barge/exhumer/industrial ship in nullsec or a wormhole.
The idea that highsec is safe, secure and untainted by the menace's of EvE simply cannot hold for much longer, people still believe that if they are in highsec, they are safe. They are wrong. I do not have much experience with nullsec, however, I believe if you and you corp found a dead end system and launched a mining op there, not only would you be more profitable, you could potentially, be safer.
I gank in highsec because I enjoy tearing the aforementioned shroud of security and safety away from these miners. I'm a bit of an asshole, yeah, I get that, but what I am doing, at the end of the day, is encouraging actions that prevents my behaviour - kind of counter productive but hey, you can't win them all.
All someone needs to do to avoid being ganked in highsec is tank their barge. When I am looking for a target I basically ignore Procurers because they are simply hard as fuck to kill, naturally, Skiffs are also off the list. What I do look for is Hulks, Covetors and Retrievers, in that order. Hulks are made of paper and I can solo most of them, same deal for Covetors and Retrievers.
tl;dr; If you want to avoid being ganked, tank your fucking ship adequately and fly in 0.7 or higher.