Space mining can absolutely cause asteroids strikes. It only hasn't done it yet because we haven't done any asteroid mining yet. A big part of asteroid mining operations will likely be asteroid herding, bringing all the asteroids you want to the same place where they can be processed. But moving asteroids around is a potentially dangerous activity.

That said, space is really really really big... It's really hard for two things to hit each other on accident. If you're collecting asteroids at a high earth orbit, the chance of them accidentally hitting earth instead is extremely low. You have to miss your target by over 100,000 miles. Which would be... a monumental failure.