Page 12 - Curriculum Visions Dynamic Book

Lead mine pollution
Lead has been mined throughout the world for centuries. However, until recently the process was not very efficient. For the most part, the ore was simply roasted to remove the sulphur, the sulphur dioxide being allowed to escape to the environment. As a result, lead smelting was a significant cause of air pollution and acid rain.
Furthermore, the gangue, which was simply piled up near to the mines, still contained considerable quantities of lead.
Lead compounds can be toxic to plants
as well as animals. As a result, little will grow on many of the spoil heaps left from decades of inefficient mining.
Because lead dissolves very slowly in water, it will take a very long time for the lead to be washed from the upper part of the spoil heaps and for vegetation to recolonise the ground. Without positive conservation measures, such pollution will remain to scar the landscape
for centuries.
 Leadville, Colorado, USA, was named after the lead deposits found at the site where the town grew up. It is in the Rocky Mountains, a site of former volcanic activity that is underlain by ancient granites.
The barren land in the foreground of this picture shows part of the spoil and also places where the ore
was roasted. The area remains barren a century after most mining ceased.
The only way the land
can be reclaimed is for the contaminated surface material to be removed and transferred to pits elsewhere. A start has recently been made on such reclamation using federal funds.
12