The strike length is unknown as the zones trend into swamp and thick overburden.
From the foxbusiness.com
Excavation initially involves the removal of any topsoil overburden by machine.
From the en.wikipedia.org
If they didn't do this, there would be huge piles of overburden next to the mines.
From the guardian.co.uk
To make matters worse, many anglers overburden themselves with gear and are unfit.
From the newscientist.com
In some locations the overburden was too deep for trenching to reach bedrock.
From the foxbusiness.com
I'm trying to approach it in a manner that's not going to overburden anyone.
From the ocregister.com
This past week saw those namesake bridges wash down like so much overburden.
From the kentucky.com
So many migrants leave their homes looking for work they overburden the rail system.
From the en.wikipedia.org
Boden used a combination of sitters at her house so that she didn't overburden anyone.
From the dailyherald.com
More examples
The surface soil that must be moved away to get at coal seams and mineral deposits
Burden with too much work or responsibility
Load with excessive weight
Overload: an excessive burden
Overburden is the material that lies above the area of economic or scientific interest (in mining and archaeology) e.g., the rock, soil and ecosystem that lies above the coal seam or ore body. It is also known as 'waste'. ...
Rock and soil cleared away before mining.
Material covering a mineral seam or bed that must be removed before the mineral can be removed in strip mining.
A layer of rocky, clay-like material directly above the oil sand deposit.