Natural Science in Archaeology

3.6 Outcrops, Mining, and Quarrying 67
rock or gangue. This material was routinely discarded at the mining site to prevent
the major expenditure of energy required in transporting it to smelting or other
metal-processing sites.
A worrying problem in Old World prehistoric metallurgy has been the dearth of
copper slag dumps from the Bronze Age. Copper smelting generates large quantities
of slag – a waste product. Perhaps later historic societies re-smelted or comminuted
some of the earlier slags that retained recoverable copper. Perhaps insufficient
intensive archaeological surveys have been conducted to locate these mounds. Prehistoric
mining of iron ores to produce metallic iron began in Anatolia about 3000
years ago and in southern Africa about 2000 years ago. Iron ores were never smelted
in the New World in prehistoric times.
Mining has always affected the landscape. Knapp (1999) calls attention to the
way mining affects relationships between society and the landscape. The problem
on Cyprus, as elsewhere, is the difficulty of finding the evidence of prehistoric mining,
then dating the evidence. In his paper, Knapp also reviews the history of the
research on prehistoric copper mining on Cyprus where production was primarily
from copper and copper-iron sulfides (chalcopyrite, covellite, bornite, and chalcocite)
occurring in mafic and ultramafic rocks. Schmidt et al. (1999) also present data
on the long-lasting effect of mining on the environment, focusing on Roman mining
in Spain.
Quarrying is the term used for “open pit” mining in which a rock product is
exploited without additional processing. Examples are marble and granite. For
more than five millennia, massive igneous, metamorphic, and sedimentary rocks
have been quarried and transported hundreds of kilometers to serve as building and
monumental stone.
The quarrying of large blocks of rock for building stone was not possible until
copper and bronze tools were invented for working the softer rocks such as limestone.
To quarry large blocks of stone, the rock must be free of closely spaced joints,
cracks, or other planes of weakness. However, some well-spaced bedding and joint
planes are necessary to permit breaking into blocks with flat surfaces. Blocks of
rock were quarried by isolating a block on four sides by means of trenches cut in the
rock and then detaching it from below by the action of wooden wedges wetted with
water. In Egypt, quarrying probably had its roots in the cutting away of limestone to
make tombs. Quarries are not easily eroded or removed from the landscape, unless
replaced by even larger, later quarries, so many landscapes are dotted with ancient
quarries. Ericson and Purdy (1984) present a broad coverage of prehistoric quarries.
Although indigenous North American peoples made extensive use of fluvial
or glacial pebbles for lithic raw materials, they also quarried bedrock. Quarrying
was the recovery method of choice where large blocks were required. In Dover,
England, in the Medieval Period, blue slate was quarried extensively, chiefly for
roof tiles as the English sought to reduce the fire danger of thatched roofs (Born
1988). Early prehistoric quarrying used fire-setting and quenching to fracture the
rock. In samples from the Kopinkallio quartz quarry in southern Finland, operated
about 9000–8500 BP, Kinnunen (1993) determined the maximum temperature
reached in the rock to be about 480°C.