National Conservation report was prepared by M. R. Campbell and E. W. Parker of the U. S. Geological Survey, and is contained in U. S. Geological Survey Bulletin 394. The recommendations there given are amplified and developed by Van Hise4 in his book on Conservation, published in 1910. Since that time the subject has been discussed by Smith, Chance, Burrows, Haas,5 and others, and certain additional conservational methods have been proposed. A considerable number of men have also discussed the sociologic and economic aspects of the question. The report of the Conservation Commission of Canada,6 published in 1915, treats rather fully of the conservation of mineral resources.
It will suit our purpose, and avoid some repetition, if we group most of these recommendations without regard to authorship. In general, these recommendations can be grouped under the heads:
(A) Methods of mining and preparation of coal;
(B) Improvement of labor and living conditions at the mines;
(C) Introduction or modification of laws to regulate or to remove certain restrictions on the coal industry;
(D) Distribution and transportation of coal;
(E) Utilization of coal;
(F) Substitutes for coal as a source of power.
(A) Mining and preparation of coal. Under this heading may be included a large number of proposals which concern primarily the engineering treatment of the coal underground and in the mine plants. Some of the more important measures are:
- Introduction of the long-wall system of mining in places where the conditions allow it, in order to minimize the waste underground.
- Modification of the room-and-pillar system of mining, by which larger pillars are left while the mine advances, and are recovered in the retreat,—thereby recovering a larger percentage of coal than under the old system, where small, thin pillars were left, which failed and were permanently lost.
It has been argued