region the average recovery of coal
in mining is 65 per cent., as against 40 per cent. only twenty
years ago. Nor are the bituminous operators any less
progressive in their conservation of the coal they mine.

In anthracite mining, powdered coal or "silt" has accumulated in
stockpiles and in stream channels to many tens of millions of tons. It
is estimated that this constitutes nearly 6 per cent of the coal mined.
Significant progress has been made recently in the recovery and use of
this silt as powdered fuel for local power purposes.

However, physical and commercial conditions do not in all cases allow of
the full application of these new methods. Once a mine has been opened
up on a certain plan, it is difficult to change it. As a whole the
longer and better organized companies are better able to change than the
smaller companies.

Conservation measures of the above kinds, as so far applied, have come
mainly from private initiative based on self-interest,--though the
cooperation of the government has been effective, particularly along
educational and publicity lines.

=(B) Improvement of labor and living conditions at the mines.= Under
this heading should be mentioned the improvement of housing, sanitation,
and living conditions; improvements in the efficiency of labor, through
making living conditions such as to attract a higher-grade labor supply
and through educational means; the introduction of safety methods; the
introduction of workmen's compensation and insurance; and other measures
of a similar nature. All these measures as a class are sometimes grouped
under the name of "welfare work."

Much thought and discussion have been devoted to the possibilities of
improvement of labor and living conditions from the standpoint of
conservation of human energy. In some quarters this subject has been
treated as being independent of the physical conservation of mineral
resources, and it has been the tendency to assume that conservation of
human energy might be more or less inimical to conservation of mineral
resources. Certain of the changes already introduced have undoubtedly
increased the cost of mining; and, until there was a general increase in
selling price, this increased cost may have had the effect of
eliminating certain practices of mineral conservation which might
otherwise have been possible. For instance, according to Smith and
Lesher:[53]

The increased safety in the coal mines tha