Alternative Title

Semiannual Technical Report Grant No. USDI H0210028 for the period ending August 31, 1971


This investigation of the combined effects of thermal weakening and mechanical disintegration (thermomechanical fragmentation) was initiated with a view toward better understanding of the processes required for more rapidly and economically fragmenting or excavating hard rock. Boring machines for utility tunnels, transportation tunnels or mining operations may be able to utilize the advantages of processes such as thermomechanical fragmentation. Secondary fragmentation or rock crushing processes also can conceivably employ the data obtained from this study.


Mining and Nuclear Engineering

Second Department

Mechanical and Aerospace Engineering


United States. Department of Defense


The research described in this report was initiated under Department of Defense Contract DACA-45-69-C-0087 wherein the effort was utilized for constructing the testing equipment for large blocks. The research on thermal weakening and pneumatic chipping was continued under Contract USDI H0210028

Keywords and Phrases

Drilling; Drilling Machines; Fracture (Mechanics); Granite; Mining Engineering; Rock Drilling; Rock Excavation; Rock (Geology); Thermal Stresses; Rocks -- Thermal properties; Rock mechanics

Document Type

Technical Report

Document Version

Final Version

File Type





© 1971 University of Missouri--Rolla, All rights reserved.

Publication Date

31 Aug 1971