Civil Engineering Reference
In-Depth Information
Table 7.2:
Primary energy consumption in stone
production
Final product
MJ/kg
Granite:
as blocks
0.3
as crushed stone
0.2
Marble
0.3
Limestone
0.3
Sandstone
0.3
Slate
Less than 0.3
(1)
Note:
(1) There are no relevant figures for slate, but we can assume
that the use of primary energy is much lower than for a block of
stone
Table 7.3:
Potential pollution during the working
of stone
Final product
Potential pollution
Granite/sandstone
Dust containing quartz
Phyllite slate/mica
"
Slate/quartzite
"
Slate/gneiss
"
Diabase/gabbro
Dust containing no quartz
Syenite/marble
"
Limestone/soapstone
"
Serpentine/clay slate
"
The lifespan of stone containing limestone can be prolonged to a certain extent
by treating the surface with linseed oil. Epoxy and silicone-based surface treat-
ments are also used. Stone is ubiquitous, even if in short supply in certain
regions. Extraction and refining is labour-intensive, consequently the use of pri-
mary energy is a lot lower than the equivalent for brick and concrete. Stone is
therefore not responsible for any significant energy pollution.
Extraction and stone crushing is usually a mechanical process with no need for
high temperatures. Various energy sources can be used, ranging from handpow-
er to wind and waterpower, either directly or as electrically-based technology.
The weight of stone suggests that the distance between quarry and building
site should be short. Quarries along the coast have the potential advantage of
energy-conserving water transport. Small, travelling extraction plants could be
moved to very small quarries near relevant building sites, employing local
labourers.
