Ruina montium

Ruina montium (Latin, "wrecking of mountains") was allegedly an ancient Roman mining technique that draws on the principle of Pascal's barrel. Miners would excavate narrow cavities down into a mountain, whereby filling the cavities with water would cause pressures large enough to fragment thick rock walls. It was described by Pliny the Elder ("Natural History" 33.21), who served as procurator in Spain.
However, there is little real evidence to show the method was used in northern Spain or elsewhere. 