Civil Engineering Reference
In-Depth Information
Table 1.1
Existing reserves of raw materials
Raw material
Statistical reserve (years)
Mineral
1.
Aggregate (sand, gravel)
Very large
2.
Arsenic
21
3.
Bauxite
220
4.
Boric salts
295
5.
Cadmium
27
6.
Chrome
105
7.
Clay, for fired products
Very large
8.
Copper
36
9.
Earth, stamped
Very large
10.
Gold
22
11.
Gypsum
Very large
12.
Iron
119
13.
Lead
20
14.
Lime
Very large
15.
Mineral salts
Very large
16.
Nickel
55
17.
Perlite
Very large
18.
Quartz
Very large
19.
Silica
Very large
20.
Stone
Very large
21.
Sulphur
24
22.
Tin
28
23.
Titanium
70
24.
Zinc
21
Fossil
25.
Carbon
390
26.
Natural gas
60
27.
Oil
40
(Source: Crawson 1992; World Resource Institute, 1992)
fallen to 0.6 per cent. Resources that have been uneconomical to extract in the past can
become a viable proposition; e.g. a more highly developed technology of stone extraction
would give this material a fresh start for use in construction. The sum of usable and less
usable resources are also called 'raw material resources', while the usable resources are
called 'reserves of raw material'.
There are also cases where developed technology has a negative impact on the extrac-
tion of raw materials; e.g. technological development in the timber industry has made hilly
forests inaccessible. It is only by using a horse that one can get timber out of such a for-
est, but it is rarely the way of the modern timber industry, despite the fact that it causes
the least damage to the forest. In the same way, modern technology cannot cope with
