This was an issue of some importance before, but it's become quite urgent now that mining is in place.

Mining being somewhat random is fine, but there needs to be a way to cull out the junk ores from the valuable stuff, since if one ventures out of the sector a station is in, it really ruins an otherwise fun and profitable activity by making you run to the station every 2 minutes to sell 30 junk ores and unload the 2 good ones.

Good point, minning really does up the priority of this in my mind as well.

I'm surprised it took all of eight hours for someone to suggest this!

Yup, we're hoping that'll be in the next update.

You could assign { and } to scroll through the cargo list. Jettison only dumps what is selected.

note that { is [ + shift and } is ] + shift

The only reason it took me this long was that I was busy mining before...

This should be a top priority in the next update - I can't see it being a terrible lot of work to impliment, and it would add IMMENSELY to the enjoyment factor of mining.