From the 1920s, the training of hewers was legally regulated as a result of union demands. Because, in the meantime, many skills required special knowledge, other tradesmen were gradually employed in mining and in the pits: initially metalworkers and, later, electricians. Following training and passing exams, the craftsman had to gain practical experience in order to sit for his hewer examination. This comprised a theoretical and a practical element.Beispiel einer Prüfungsordnung für einen Maschinenhauer (retrieved 13 September 2012)
