Coal Resource Classification System of the U.S. Geological Survey
By Gordon H. Wood, Jr., Thomas M. Kehn, M. Devereux Carter, and William C. Culbertson
GEOLOGICAL SURVEY CIRCULAR 891
Figure 11 - Determination of areas of reliability using coal thickness measurements taken along a continuously exposed, strip-mined bed, supplemented by drill-hole data |
Created by the EERT WWW Staff.
[an error occurred while processing this directive]