archaeological & built heritage assessment - The Heritage Council

opening of railways to areas of outstanding natural beauty such as that within the study area facilitated the
development of tourism on a scale not previously envisaged.
Mining Industries
While minerals have been worked in Ireland from the earliest stages of its history, it was mainly during
the nineteenth century that mining activity accelerated. Relative to Britain, coal and metal resources were
modest and mining activities were consequently scattered, intermittent and economically marginal,
undertaken only when market conditions for particular minerals were favourable. As such, mineral
exploitation was too weak to stimulate the indigenous growth of heavy industry associated with the
Industrial Revolution.
Coal
Ireland’s coal deposits were worked from the seventeenth century onwards, arousing increasing interest
from about the middle of the eighteenth century. Irish coal deposits are in carboniferous strata broadly
similar to those of England, Scotland and Wales. However, whereas the coal measures of Britain were
well preserved, their Irish equivalents were seriously eroded; twisted and contorted by geological
movements, they were difficult and expensive to mine (Aalen, Whelan & Stout 1997).
There are various coalfields around Ireland- including Ballycastle, Coalisland, Castlecomer, and even the
Kish Bank in Dublin Bay. Most are small and the coal was often of poor quality, and though they were
mined on and off over the centuries, it was usually easier to use local wood or turf as a fuel or even to
import coal from abroad (Mulvihill 2002). However, the Arigna coalfield near Lough Allen was worked
until 1990, making it the last large-scale coal mine in Ireland. The best deposits are found to the west of
the lake, on either side of the Arigna river between counties Leitrim and Roscommon, although it is still
only of fair quality since it produces nearly 40% ash.
Ironworking
Iron is a common element and widely distributed throughout the earth’s surface, but always as a rocky
ore containing earthy materials and other minerals. As such, the making of iron always entails some
processing, and its appeal as a metal began only with the development of reasonable smelting techniques.
Iron smelting originated in the Middle East 4000 years ago and spread slowly across Europe, arriving in
Ireland c. 400BC. Early smelters were simple clay ovens where lumps of ore were placed on top of hot
charcoal. A manual bellows eventually reduced the ore to wrought iron that could be hammered into
shape. By the medieval period, ironworks were using waterwheels to operate more powerful bellows and
hammers, and hence had to be built near a water source.
In the fifteenth century it was discovered that purer iron could be produced if the ore was smelted with
the charcoal, rather than on top of it. This led to the blast furnace, a tall oven with an opening at the top
where the charcoal and ore were introduced, and a facility at the base where molten cast iron was let out
(ibid.). The next improvement came when it was discovered that adding limestone to the furnace
produced and even cleaner iron, because the limestone combined with the earthy ore to form a slag from
which the molten metal readily separated.
Blast furnaces introduced a major change in iron smelting techniques. They consumed vast amounts of
charcoal and since coppicing was seldom practiced in Ireland, once the trees around the ironworks were
22