Link to USGS Home Page

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 16 - A simple valley reentrant with construction of 14-inch minimum thickness limit
PREVIOUS   NEXT

Created by the EERT WWW Staff.

[an error occurred while processing this directive]