Ancient Roman Mining and Quarrying Techniques
Read this article about Roman mining to learn how ancient Romans solved its technical problems. They even had mechanical devices for removing modest amounts of water from mineshafts.
Stone Masons and Quarrying Techniques
Lifting Connections
Figure 16: Typical Roman lifting connections
Romans took after two of the Greek methods of lifting; handling bosses and lifting pins, and invented the use of grips. Evidence for these methods can be seen today at archaeological sites. During our visit to the Flavian Amphitheater, we saw holes in many of the stones in the walls and learned that lifting pins used to be there. The metal was later stolen by thieves.
Handling Bosses
Handling bosses were symmetrical protrusions on two opposite sides of the rock face where rope slings could be attached for lifting. Occasionally four bosses have been found on larger stones, probably for added stability when lifting. This method was discovered on sites where work was interrupted because the protrusions were removed after the stone was placed. Greeks carved U shapes into stones instead of making protrusions so that the extra work of removing handling bosses at the end of the project was eliminated.
Lifting Pins (Lewises)
This system consists of 3 separated metal rods with cavity holes which are all anchored into the stone. A horseshoe shaped hook with the same size cavities is put in between the metal rods such that the cavities line up. Lastly, a bolt is passed through all of the holes to form the lifting pin. When considering the connection's strength, it was always the stone that broke first. Therefore, the depth to which the metal rods were anchored into the stone was increased with load size rather than the thickness of the lifting pin itself.
Grips
Pincer grips required the least amount of preparation, it was only necessary to make sure that the end of the grip dug into a small hole in the stone. Lifting action further increased friction between the grip and stone because the pincers acted like a pair of scissors: the weight of the stone forced the forceps together, digging the grips further into the stone. If the grips were put on the faces of the stone that would not be part of the exposed surface, it isn't possible to tell that this lifting technique was used as the holes are hidden from sight.