Minewatch Asia Pacific - Philippine Indigenous Peoples Links Briefing Paper, April 1999Published by MAC on 2001-05-01
Minewatch Asia Pacific - Philippine Indigenous Peoples Links Briefing Paper, April 1999
The Destruction of Construction:
a critique of the cement industry
by Roger Moody
"Dad made the soil both rich and dark
and granddad built a wooden shack.
Developers were turned away...
Workmen dumped a mound of clay
But this old patch kept fighting back"
[This Blessed Plot: The Albion Band, c. 1998]
The main use of cement is in construction and infrastructure, and cement factories have traditionally been located close to limestone quarries - limestone being the key ingredient of cement manufacture. However, depending on the quality of the cement required, other materials are also needed: shale, clay, gypsum (which provides an average 5% of input to cement manufacture) marble, iron ore, dolomite. In some areas, high alumina clays (a byproduct of bauxite mining) are much sought after (1). Rock containing sulphates is also employed in the manufacture of "super sulphate" cement. In brief, a wide variety of raw materials is employed in cement production, giving the final product different types of bulk, flexibility, durability and strength.
However, this presents the key problems of cement manufacture: the mining of the raw materials, and the fuelling of the kilns which burn - and concentrate or "purify" - the raw materials at very high temperatures, can both be highly detrimental to the environment and to the health of workers and residents in the neighbourhood of the plants.
Cement production carries with it a "triple jeopardy" (2). First, the raw materials contain toxics (sulphates, sulphides, pyrites, nitrogen) which should be neutralised and captured in the burning process. Second, mining them releases huge quantities of dust and creates spoil heaps (as with limestone quarries). These can directly threaten the lives of workers (through the contraction of pneumoconiosis, cancer, silicosis, and other lung diseases) and damage the quality of air for communities at large. Surrounding vegetation gets blanketed and stifled with dust and particulates. Water courses may be destroyed, blocked, or impaired (e.g., through increased alkalinity caused by excesses of lime). Third, the fuels commonly used in cement kilns (oil, wood, coal, industrial and domestic wastes) are often high in sulphur and nitrogen.
The world's big cement manufacturers have taken some steps to limit these damaging impacts: in many countries, they are compelled to install flue gas desulphurisation, carry out "pre-calcination", reduce nitrous oxides (NOx) and capture particulates (stack emissions), to avoid the choking of entire local populations. There is an obvious cost to implementing such minimum standards. And, as with standards for other forms of mineral processing, they are not applied consistently or worldwide. Indeed, even in "advanced" countries, such as Britain, regulations on cement storage have recently been relaxed, as the industry argued successfully that continual monitoring of dust levels was too expensive and unnecessary.