AchtJahrzehnte Gefrierverfahren nach Putsch

SUBJECT AREA: Mining and extraction technology

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Pötsch was the son of a forest officer and could not easily attend school, with the consequences that it took him a long time to obtain the scholarly education needed to enable him to begin work on a higher level with the mining administration in the duchy of Anhalt in 1868. Seven years later, he was licensed as a Prussian mining surveyor and in this capacity he worked with the mining inspectorate of Aschersleben. During that time he frequently came across shafts for brown-coal mines which had been sunk down to watery strata but then had to be abandoned. His solution to the problem was to freeze the quicksand with a solution of chloride; this was better than the previous attempts in England to instal cooling coils at the bottom of the shaft. Pötsch's conception implied the construction of ice walls with the means of boreholes and refrigerators. By his method a set of boreholes was driven through the watery strata, the smaller pipes contained within the main bore pipes, providing a channel through which calcium chloride was pumped, returning through the longer pipe until the ground was frozen solid. He obtained a patent in 1883 and many leading international journals reported on the method the same year.

In 1884 he established the Internationale Gesselschaft für Schacht-, Brucken-und Tunnelbau in Magdeburg and he also became Director of the Poetsch-Sooy-Smith Freezing Company in New Jersey, which constructed the first freezing shaft in America in 1888.

However, Pötsch was successful only for a short period of time and, being a clumsy entrepreneur, he had to dissolve his company in 1894. Unfortunately, his decision to carry out the complete shaft-sinking business did not allow him to concentrate on solving upcoming technical problems of his new process. It was Louis Gebhardt (1861–1924), his former engineer, who took care of development, especially in co-operation with French mining engineers, and thus provided the basis for the freezing process becoming widely used for shaft-sinking in complicated strata ever since.

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