One obvious element that was already present in the theme was the occurrence of Rock Monsters and Energy Crystals in the story. However, in the Lego Power Miners, the Rock/Lava Monsters play a bigger role and are included in every set and each Rock/Lava Monster are all named characters with different personalities and traits.
The Lego Power Miners and Lego Rock Raiders theme both have settings that take place underground and both themes have each team search for crystals, whilst trying to prevent the Rock/Lava Monsters from eating them. However the difference is while the crystals in Lego Rock Raiders were Energy Crystals with massive power in them, the Lego Power Miners crystals seem to be kinetic energy based instead. While Lego Power Miners collect their crystals for research purposes, the Rock Raiders collect them as fuel for their ship. Another difference between the themes is that the Crystals eaten by Rock Monsters in Power Miners make them release the kinetic energy, causing massive rumbles when underneath the surface.
The Cargo Crusher is a LEGO Power Miners set made from the pieces of the Granite Grinder. The Instructions for this set so far have only been found in New Zealand. This sets(with 68 current pieces) main function is a rotating drill that drags a Glaciator behind it. Glaciator is hooked up to a chain so he can't escape, and is well away from the blue crystal and dynamite.
The Rock Watchman is a LEGO Power Miners set made from the pieces of the Titanium Command Rig. It has a crusher wheel at the front, a cage for a Glaciator which is held by a crane and a small cabin.