THE MINERAL INDUSTRY OF MINNESOTA 
391 
 
 Sulfur.—Great Northern Oil Co. and Northwestern Refining Co. continued
recovering sulfur as a byproduct from their petroleum refining operations
near Pine Bend, Dakota County, and St. Paul Park, Washington County, respectively.

 Vermiculite.—Three Twin Cities firms produced exfoliated vermiculite
from material shipped from outside the State. The expanded vermiculite was
sold for use principally as aggregate in lightweight plaster and concrete.

MINERAL FUELS 
 
 Peat.—Three companies reported peat production in Minnesota in 1972.
It consisted principally of moss and reed-sedge peat used in general soil
improvement and in potting soils. Most was sold in packaged form, but some
minor quantities were sold in bulk. Although Minnesota has 50% of the Nation's
known peat supply, it produces only a very small fraction of total US. production.
It accounts for less than 1% of State mineral production value.