lude the
elimination of resource or royalty costs, the control of
over-capitalization, the removal of restrictions on concentration of
control, the granting of permission for cooperation among competitive
units, the regulation of selling price minimums in order to insure
during normal times the use of better physical practices, and the
control of distribution. In short, it appears that there are two great
spheres of conservational activity--one within the field of private
endeavor, and the other possible only by collective action through the
government. The principal advances thus far made have been in the field
of private endeavor.

The government has aided greatly in the advancement of conservation
measures arising within the field of private endeavor. One need only
refer to many governmental investigations, to the spreading of
information as to best methods, and to local compulsory requirements
that the best practices be made uniform and that backward interests
thereby be brought into line.

Recognition of the fact that there is a large body of sound
conservational practice in the coal industry which falls within the
range of self-interest seems essential in planning further changes in
the direction of conservation. Conservational measures do not all
require sacrifice of the individual to the public, nor of the present to
the future generations. An exercise of public power is not in all cases
essential to the advancement of conservation. The respective limits of
the fields of public and private endeavor are not sharply defined, and
vary from place to place and time to time, depending upon local
conditions and special requirements.

In general, the sphere of private interest includes measures which will
bring adequate commercial return. The interest rate is the limiting and
controlling factor. When it is possible--by improvement of methods of
mining, better planning, better preparation of coal, better
transportation and distribution, or better utilization--to secure a
larger average return on the investment, or to insure return through a
longer period of years, self-interest naturally requires the
introduction of such methods as rapidly as financial conditions allow.
Even some of the improvements in labor and welfare conditions have been
introduced in this way, with a view to securing a more permanent and
more efficient labor supply, and thereby aiding the enterprise from the
commercial standpoint.

Within the s