Environmental Engineering Reference
In-Depth Information
date to 1325. But coal burning was never any more than
a marginal source of energy in ancient or medieval soci-
eties, and it had no influence on determining the techni-
cal development of those societies (Nef 1932). England
was not the first country to shift from phytomass to a fos-
sil fuel. That primacy belongs to the seventeenth-century
Netherlands, when the Golden Age of the country's
economy and creativity was energized largely by peat
(DeZeeuw 1978).
But England was the first country to accomplish the
shift from phytomass fuels to coal, and this conver-
sion preceded the often described onset of the late-
eighteenth-century industrial revolution by some 200
years (Nef 1932; J. R. Harris 1974). During the six-
teenth century demand for coal was rising steadily, and
by the beginning of seventeenth century the fuel was
commonly used in households as well as to make bricks,
tiles, earthenware, glass, starch, soap, and sugar, and to
extract salt. Between 1540 and 1640 mining began at all
major English coalfields, and between 1580 and 1660
coal shipments to London rose about 25 times. The
ensuing emissions gave the city a deserved reputation as
being unfit for human habitation. By 1650, Britain's an-
nual coal output passed 2 Mt; 3 Mt were extracted by
the early eighteenth century, and over 10 Mt by its end
(Hatcher et al. 1984-1993). Coal did not simply sup-
plant wood. Its large-scale use required solving many
technical and organizational problems connected with
its mining, transport, and industrial uses.
Rising coal demand led to larger and deeper mines
as the small surface pits or shallow shafts producing just
1-2 t/day were replaced by larger collieries. The deepest
shafts surpassed 100 m in the early eighteenth century
and reached 200 m by 1765 and 300 m by the 1830s.
Extraction was initially energized solely by human labor.
Hewers, working with picks, wedges, and mallets, were
assisted by putters filling baskets, loading them on
wooden sledges, and dragging them to pit bottom.
There onsetters hung the baskets on ropes, windsmen
hauled them up, and banksmen carried them to storage
heaps. Boys as young as 6 years did lighter tasks, and the
heaviest work often fell on women or teenage girls as
they carried coal to the surface by ascending a series of
ladders with heavy baskets tied to forehead straps (Ash-
ton and Sykes 1929).
The severity of these exertions was incredible. Ascend-
ing 35 m to the surface with up to 75 kg of coal trans-
lates, when assuming body weight of 60 kg and speeds
of about 0.2 m/s, to exertions of close to 300 W, clearly
near the limit of human performance, especially when
considering the precarious nature of the task. This is a
painful illustration of the inevitability of subsidizing the
introduction of a new energy source by liberal use of
the dominant energy, in this case the exertion of female
muscles. Where human muscles were inadequate, horses
became indispensable for powering the whims or tread-
mills used for pumping water from deep shafts and for
hoisting coal from larger pits.
After 1667 horses and donkeys were also used under-
ground for hauling. Waterwheels and windmills did some
of the pumping and hoisting, and they and the horses
were only slowly replaced by Newcomen's very inefficient
steam engines, which converted just 0.5% of coal into
useful motion. Until the widespread employment of
steam engines, both coal mining and transport were
overwhelmingly energized by animate labor. Transporta-
tion of coal in heavy horse-drawn wagons was feasible
only over short distances. The use of ships for longer dis-
tances led to extensive development of canals, whose
era ended only with the expansion of railways. Coal
