While the art of tunneling soft ground is of relatively recent origin,
that of rock tunneling is deeply rooted in antiquity. However,
the line of its development is not absolutely direct, but is
more logically followed through a closely related branch of
technology--mining. The development of mining techniques is a
practically unbroken one, whereas there appears little continuity or
relationship between the few works undertaken before about the 18th
century for passage through the earth.
The Egyptians were the first people in recorded history to have driven
openings, often of considerable magnitude, through solid rock. As is
true of all major works of that nation, the capability of such grand
proportion was due solely to the inexhaustible supply of human power
and the casual evaluation of life. The tombs and temples won from the
rock masses of the Nile Valley are monuments of perseverance rather
than technical skill. Neither the Egyptians nor any other peoples
before the Middle Ages have left any consistent evidence that they
were able to pierce ground that would not support itself above the
opening as would firm rock. In Egypt were established the methods of
rock breaking that were to remain classical until the first use of
gun-powder blasting in the 17th century which formed the basis of the
ensuing technology of mining.
Notwithstanding the religious motives which inspired the earliest rock
excavations, more constant and universal throughout history has been
the incentive to obtain the useful and decorative minerals hidden
beneath the earth's surface. It was the miner who developed the
methods introduced by the early civilizations to break rock away from
the primary mass, and who added the refinements of subterranean
surveying and ventilating, all of which were later to be assimilated
into the new art of driving tunnels of large diameter. The connection
is the more evident from the fact that tunnelmen are still known as
miners.