Olympia: The Age of Gods PBEM (May 4 1999)
Time to learn: 21 days. Time to use: 14 days. Requires: ten workers [11] (not consumed) Requires: ten iron [79]
Use of this skill adds iron shoring to a mine shaft. Normally the chance each month of a cave-in in a mine shaft is (depth/300)%. Iron shoring reduces this chance by 4.6%.