Keep the density/scrolling speed relationship for skill.
The deposit quality display doesn't make sense though. A big blue section should be a big, high quality deposit. A little blue section should be a little deposit. However, depending on how well you trigger the missile in the center of the blue section, this determines how big or or more dense chunk you get. So you still need the skill of exploding the missile at the right time, but you naturally thing bigger is more. If you're too early or too late, the chunk is low quality.
So you basically need to perform the same actions, but the meaning of the blue zone is reversed.
The deposit quality display doesn't make sense though. A big blue section should be a big, high quality deposit. A little blue section should be a little deposit. However, depending on how well you trigger the missile in the center of the blue section, this determines how big or or more dense chunk you get. So you still need the skill of exploding the missile at the right time, but you naturally thing bigger is more. If you're too early or too late, the chunk is low quality.
So you basically need to perform the same actions, but the meaning of the blue zone is reversed.