Planets mining is, quite literally, the dismantling of planets and moons on a macro-scale. Entire worlds are fractured to reveal the rich seams of valuable minerals contained inside. Despite environmentalist concerns, the operation is perfectly safe and is the only way to extract the necessary resources on the large scale required to supply Earth and the colonies.
You may have read reports that claim the destruction of a planet can destroy an entire solar system due to the disruption in the gravitation forces that hold each celestial object in orbit. Concerned investors are directed to read the article "The CEC Pledge to the Health of Our Universe" for a detailed breakdown of the truths about Planet Cracking.