Since the beginning of the industrial age, man's impact on this
planet has become ever more harsh. The natural landscape has been
squeezed into smaller and smaller areas.
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| Surviving tower above former New Almaden mine reduction works, H Graem © 2008 |
At times, with man's conscious help or more often by happenstance,
nature has reclaimed her birthright. An example of the former is the
reclamation of rock quarries into parks. An example of the latter is
the reforestation of eastern North America following the (1) opening to
settlement of the Midwestern prairies and (2) cessation of demand for
pasture land for horses with the commencement of the automobile age.
An extreme example of nature reclaiming it's own may be found at the
site of the Chernobyl nuclear accident. The radiation generated in this
incident resulted in the removal of all human inhabitants over a large
swath of land surrounding the site. Amazingly wildlife, including wolves and bison, have reclaimed the land and thrived in the
Chernobyl Exclusion Zone.
New Almaden Quicksilver Mine
Rebirth of nature on lands impacted by the processing of toxic substances, such as the mercury involved at the
New Almaden Quicksilver mine, can be most gratifying. Before and after images below of various sites at the former mine show the progress in reclamation since the mining era ended.
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| Liquid Mercury |
In the 19th and early 20th centuries mercury was a primary ingredient
in the manufacturing process for hats and in refining gold. Mercury is one of the most toxic elements. Such
toxicity is a key characteristic of the mining and processing of
mercury. Pure mercury is a liquid metal, sometimes referred to as
quicksilver that volatilizes readily. Mercury in the air
eventually settles into water or onto land where it can be washed
into water. Once deposited, certain microorganisms can change it
into methylmercury, a highly toxic form. The term 'crazy as a hatter' is
indicative of its toxicity to workers in that industry. The principal
source for mercury is the red ore called Cinnabar.
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| Historic Almaden mine drawing - Courtesy UC Berkeley digital library |
Starting around 1849 with the California Gold Rush, the largest
American source for Cinnabar was the New Almaden Mine in the Santa Cruz
Mountains at the south end of San Francisco Bay.
The mining of this ore lasted over 100 years. The oak forest which previously covered the hills was clear cut to provide fuel for the furnaces. Industrial and residential buildings were constructed and then torn down as the quality of ore decreased and mining operations terminated in different areas and miners departed
their homes on the company land.
Approximate dates when operations ceased for various locations within the mining area are as follows below:
- Spanish Town - Last of inhabitants gone in 1900
- Hacienda Reduction Works - dismantled following closure in 1912
- English Town - Last of inhabitants gone about 1912, Buildings removed in 1930s.
- Senador - Closed in 1926 and reduction plant dismantled
With exhaustion of the richest pockets of ore, the last of the
mining ended about 1970. By 1975 all of the land owned by the former mining
company had been acquired for a county park.
The cleanup began immediately. In many cases, exposed bodies of mine tailings were
covered with impermeable layers of clay to minimize transport of
mercury to water bodies.
The 'before' and 'after' photos below
illustrate the restoration of this formerly mined land and its return
to a natural state. Given the reclamation difficulties involved in this
Mediterranean climate and the extent of mercury contamination, the reclamation of these mined areas gives hope for other lands damaged by the ravages of man.
Before After
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| English Town from schoolyard - Circa 1885 Today with increased tree cover |
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| Senador Mine - Circa 1916 Concrete dust bins remain standing |
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| Hacienda Reduction Works - Circa 1875 Undergoing Mercury Decontamination |
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| Spanish Town - Circa 1890 Oaks on north facing slope recovered nicely |
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