Kohler’s Last Strand
Pennsylvania Coal v. Mahon
274 Pa. 489, 260 U.S. 393 (1922)
A Pennsylvania law prohibited the mining of coal where the mining might cause the subsidence
of any improved property.
Mahon had acquired surface rights from the Pennsylvania Coal
Company, but had signed a waiver of liability in exchange for a substantially reduced price.
After enactment of the statute, Mahon brought suit to enjoin the coal company from mining the
coal under the Mahon's land and thereby prevent the subsidence of their home.
company contended that the regulation amounted to a taking of private property without due
process of law.
The material that was gradually transformed into anthracite coal was deposited during the
Carboniferous Geologic Period (400-250 million B.C.).
At that time, most of what is now
Pennsylvania was a hot, humid greenhouse of steamy swamps, towering trees, and spreading
Property rights were not clearly defined.
The anthracite coalfield encompasses nearly 500 square miles across the Eastern third of
Economic and social development advanced along with the mining activity; by
1920, the many cities, boroughs and villages sported a combined population of about one million
people. When this locale was sparsely peopled, sporadic cave-ins were sources of personal and
local tragedy, but not major public events.
However, during the decade preceding this case,
public welfare and safety were being threatened.
Streets and buildings were collapsing, with
substantial risk of injury and loss of life.
At least, that is what was suggested in the preamble of
the 1921 Kohler Act:
The anthracite coal industry in this Commonwealth has been and is being carried on in
populous communities in such a manner as to remove the entire support of the surface of
the soil to such an extent as to result in wrecked and dangerous streets and highways,
collapsed public buildings, churches, schools, factories, streets, and private dwellings,
broken gas, water and sewer systems, the loss of human life, and in general so as to
threaten and seriously endanger the lives and safety of large numbers of the people of the
Pennsylvania law had always held that the surface owner was entitled to support.
owners frequently waived support rights when purchasing the surface rights from coal
In fact, a 1917 case (
Penman v. Jones
) acknowledged a “support estate” that was
distinct from the “subsurface” (mineral) and “surface” estates.
A coal company had sold the
surface property to a homesteader, maintaining the right to mine the coal without liability for
Eighteen years later, it conveyed the mineral rights to a steel company, but failed to
transfer the waiver of liability.
As a result, the
reverted back to the homesteader.