Doctoral Dissertations


"This thesis describes an investigation of the relationships among the composition, physical properties and the performance of roof shales in Illinois coal mines. The study included cataloging the physical and mineralogical properties of typical roof shales, determining the interrelationships of the properties and defining the factors in the rock which effect deterioration. From the results, a classification system has been developed which may provide a means for evaluating coal mine roof stability.

A coring apparatus was developed for obtaining in situ samples from mine roofs. Five coal mines with varying geologic and roof conditions were sampled. Precautions were taken to preserve the samples in their natural condition. Laboratory tests were performed to determine the composition and physical properties of the samples. Tests to determine composition included: particle size analysis, x-ray diffraction, differential thermal analysis, chemical stain, and fabric analysis. Tests to determine physical properties included: unconfined compression, triaxial shear, slaking-durability, hardness, porosity, permeability, apparent specific gravity, point load and natural moisture.

A comprehensive statistical analysis was made on the test data to determine the interrelationships of the shale properties. Among the significant relationships it was found that natural moisture content and scleroscope hardness were related to: clay mineral composition, compressive strength, and slaking durability. From the statistical analysis and performance history of the shales in the mines a classification system for roof stability was devised based on natural moisture content and scleroscope hardness.

A suggested testing program is presented as an Appendix. This program outlines the procedure which a mine operator would follow to predict the performance of the mine roof"--Abstract, page iii.


Aughenbaugh, N. B.

Committee Member(s)

Scott, James J.
Haas, Charles J.
Rockaway, John D.
Schmidt, Norbert O., 1925-2009


Geosciences and Geological and Petroleum Engineering

Degree Name

Ph. D. in Geological Engineering


United States. Bureau of Mines


Financial assistance was provided by the U. S. Bureau of Mines contract No. H0111462 which was authorized by the Federal Coal Mine Health and Safety Act (P.L. 91-173; 83 Stat. 742).


University of Missouri--Rolla

Publication Date



xi, 111 pages

Note about bibliography

Includes bibliographical references (pages 97-103).


© 1973 Peter J. Conroy, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Subject Headings

Coal mines and mining -- Illinois
Shale -- Illinois -- Testing
Mine roof bolting

Thesis Number

T 2803

Print OCLC #


Electronic OCLC #