I'll second Errantdreams on the Ore Theft issues. I am a miner by trade and have had multiple run-ins with ore theives even in high security areas. Here's my tips to keep you ore secure:

If you are alone then you can work up to the 'Anchoring' skill, and a hauler tht will pack more than 3000m3, and use Giant Secure Containers. These can be dropped in belts and anchored (i.e. they stay put permanently and don't pop) as long as they are 5000m for any object. You can fill one or a few of these and then bring the hauler out and empty them. Until you get onto larger mining vessals this is pretty practical. Once you get inot a tier II or tier III barge though it starts to get more difficult. A lot of industrial corporations do this for members.

My solution, and one that most serious miners eventually take up, is to get a second account. This means as one character is loading the jetcan the other can unload it, this meaning there is rarely any hanging around for the sticky fingered to grab.

Now I know not everyone can afford to do this, and hotboxing is seen as unfair by some people. However CCP have got to a lot of effort to cut the cost a little (they run a 'Power of 2' offer every so often) and they also make the client able to run more than once on a single computer so you don't need 2 computers. I have to say I find an alt great as not only does it give you greater mining output and efficiency, it also means you can persue 2 or more career/skill paths. One of my characters is a miner, the other is a combat pilot (with lvl 5 industrial skills for hauling).

Hope that helps!