Mornings, regular haulage comes inside compound (7)
I believe the answer is:
amalgam
'compound' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for amalgam that I've seen before include "Blend or combination" , "Mercury alloy - combination" , "combination of things" , "Alloy of mercury and another metal" , "Compound" .)