The Washburn leader. [volume] (Washburn, McLean County, N.D.) 1890-1986, 1913-03-07
Facts About Lig-.
mite Coal Fields

More Coal Mined In This State IN
1912 Than IN Any Other Year
Says Mine Inspector
Following is the address of DR.. A. G.
Leonard, state geologist, before the
North Dakota Society of Engineers:
The Ignite coal fields Of North Da-
kota cover an area of approximately
5000 square miles in the western part
of the state and the total tonnage of
workable coal has been estimated at
500, ,0OO, ,0O0,0 No other state in the
union has so much coal as has North
Dakota, and few realize the vastness
of our resources in this valuable mineral.
The coal beds are confined to two
formations, namely, the Fort Union
and Lance. The Fort Union is one of
the most important and best known
formations of the northwest. It covers
vast area east of the Rockey noun
tains, stretching from Wyoming to the
Arctic ocean in the valley of the
Mackenzie river, including several
Canadian provinces, much of North
Dakota, eastern Montana, southwest
ern South Dakota and eastern Wyom-
ing.
The Fort Union is fresh water for
nation, the beds having been deposited
in large lake or lakes, and is COM
posed of clay shales, alternating with
sandstones, and containing many beds
of Ignite. 1t is remarkably uniform
in color, composition and appearance
throughout the region. The prevailing
color is either light ash grey or yell
low, but in places the beds are almost
white. The Fort Union formation
everywhere contains numerous beds of
Ignite coal.
The Lance formation has wide dis
tribution in North Dakota and eastern
Montana, as we'll as in parts of South
Dakota and Wyoming. The largest
area in North Dakota is the south
central part of the state. A smaller
area is found in the southwestern cor
ner of the state. In Morton county
this formation is found to consist of
three members: an upper sandstone
about 100 feet thick, middle member
composed of dark shales with few
sandstone layers and having thick
ness of 200 to 250 feet, and lower
division made up of shales and sand
stones in alternating layers. This later
member has thickness of $50 feet or
over, and the maximum thickness of
the entire Lance formation is not far
from 700 feet in this region.
In southern Billings county, partic-
ularly in the vicinity of Yule, and at
several points in Morton county, work.
able beds of Ignite are found in the
Lance formation, but throughout most
of its area the latter is barren of coal
with the exception of thin seams only q
few inches thick. In the Fort Union
formation, on the other hand, one rarely
:finde an .outcrop where several hundred
feet of strata are exposed that does not
contain at least one or more coal beds.
These range from top to bottom of the
formation, and do not appear to be
confied to any particular horizon or
horizons.
1t was formerly supposed that the
Ignite beds were not of great extent
and covered but comparatively small
areas, one seam thinning out and being
replaced by others at different hori-
zon. But the detailed work of the past
few years has shown that some of the
individual coal beds cover large areas.
One, with thickness varying from five
to sixteen feet, has q known extent of
twenty milesin one direction and twenty
five in another, with an area of at least
500 square miles, and probably much
greater. Another bed of coal was trac-
ed thirty-six miles north and south and
twenty-four miles east and west, and
while its known area as shown by out
crops is nearly 800 square miles, il
undoubtedly has an extent of 1000 to
1,5O0 square miles. This coalbed, which
has q thickness ranging from nine tc
fifteen feet and over, has been largely
burned out or removed by erosion, but
still underlies number Of townships.
The Ignite coal beds of the STATE
vary in thickness from less than ar
inch to thirty-five feet, q bed of the
latter thickness occurring on Sand creel
in southern Billings county. Severa
beds twenty feet thick are known ant
seams six, eight and ten feet thick ar.
common.
During the past six or eight year,
the North Dakota Geological survey
has studied in more or less detail thu
- Gn0l NJ