Speculative Borings in the Earth's Crust

Abstract

THE heat generated in the interior of the earth's crust has puzzled men of science for centuries. In recent years, radical changes have been made in the theory of what causes this heat. A modern theory is that there is no heat from radioactive materials at greater depths than 12 miles. Heat is also due to the oxidation of iron and friction of slipping rocks. The present high price of gold has turned the attention of South African engineers to the possibility of boring their mines deeper. In the Heaton Works Journal of June an interesting account is given of the work done by Sir Charles Parsons in this connexion, and on the proposals he made for sinking a bore hole 12 miles deep. He proposed an arrangement of brine-cooling by large steel pipes connected at the top and bottom of each half mile section by a closed ring. There would be air-locks also every two or three miles so as to prevent the air pressure from becoming excessive. The real difficulty in the way of boring a hole to a great depth lies in the cost of the undertaking, and in the fact that a financial return cannot be guaranteed. Practically the only inducement to business men to explore the depths of the earth by sinking a deep hole is the chance of finding rich deposits of precious metals. If this is ever done it would put the speculations of men of science to the acid test of practice.