Use bi-weave shields. They regenerate much more quickly between bumps.
That's about the best thing you can do to "specialise" a mining ship's shield.
Kind of like with combat, 500mj of shield that can re-generate in 30 seconds is a lot more useful than 1000mj of shield that takes 10 minutes to regenerate.
If you're feeling brave, try deploying your cargo scoop and then ramming a 'roid at full-speed.
Alternatively, try detonating a DC roid while you're only a hundred metres from it.
If your shield can absorb that kind of abuse
and recover quickly, so it's ready for the next time, you're doing it right.