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 coöperation 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:12