Techniques started to improve during the Renaissance:
* In order to dig beyond a certain depth it was necessary to be able to pump out the water that often found its way into mine shafts and underground structures. Piston pumps had been invented in ancient Greece (by Ctesibios of Alexandria) in 270 BC but they not were sufficiently improved to be suitable for use in mines until the XVth century.
- The use of gunpowder had been known in the West since the Middle Ages. This “black powder” was produced by mixing sulphur, charcoal and saltpetre (potassium nitrate). However, for rock blasting, explosive could only be used if an explosion could be set off safely. This was not impossible before the development of the “slow fuse”. The use of gunpowder in mines therefore dates from the year 1613.
- At the end of the Renaissance, indeed before the end of the eighteenth century, there was still no mechanical means available for drilling blast holes in which to place explosive, . The holes had to be made by hand by hitting a "jumper" (a heavy metal bar) with mallets.
- Engineers were still unable to perform the mathematical calculations which make it possible to estimate, on the basis of laboratory measurements, the stresses exerted by soil and evaluate the risks of collapse.
Such developments did not take place until the end of the eighteenth century.
The Malpas tunnel is a remarkable structure from this period.
The large circular drain in Paris, 6128 m long and 2 metres high was finished in 1740.
Find out more :
- The Malpas tunnel (Format pdf - 72.1 kb - 25/02/2008)