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State of Conservation (SOC)

Humberstone and Santa Laura Saltpeter Works

Humberstone and Santa Laura Saltpeter Works
Date of Inscription: 2005
Nomination records (Year): 2004, 2011
Category: Cultural
Criteria: (ii)(iii)(iv)
Danger List: Yes
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  • Deliberate destruction of heritage
  • Management systems/ management plan
  • Wind
  • Other Threats:

    a) Extremely fragile nature of the industrial buildings that were constructed using local materials such as timber for frames, corrugated iron sheets for roofs and some walls, in addition to stucco and lightweight constructionb) Lack of maintenance over the past 40 years c) Corrosion of metal cladding and dismantlement of some of the structural elements. A few buildings such as the Leaching House are liable to structural collapse if no support is givend) Very little conservation work carried out

Inscription on the Danger List
Year: 2005
Threats to the Site:

The main issue is the extremely fragile nature of the buildings. As with most mining buildings, they were constructed using local materials and lightweight construction that functioned with regular maintenance and could be altered in response to changed circumstances. At Humberstone and Santa Laura the materials used were timber for frames, corrugated sheet for roofs and some walls, and stucco. There has been no maintenance for 40 years, and there has been damage and vandalism as well as some dismantling. The metal cladding has corroded and some of the structural elements dismantled. A few buildings, such as the Leaching house, are liable to structural collapse if no support is given.

The greatest threat is from looters searching for re-usable materials. During the time when the works were closed and still in private hands much was lost. Looters look for all sorts of memorabilia on the sites such as timber, bottles, coins and tokens. Although looting has dwindled, the Douglas Fir is much prized and, as it is now nationally protected in the USA, prices for it have risen. Timber was stolen from the Santa Laura Leaching plant in 1999.

Although the site is a virtually rain-free desert, windborne salt from the coast has an impact on the metal sheeting causing corrosion. Wind has also affected the wooden structures: those painted have been given a protective mineral coating by the salty wind whereas those unpainted have been eroded by the wind.

In summary: 

a)         Extremely fragile nature of the buildings;

b)         Lack of maintenance for 40 years;

c)         Vandalism due to looting of re-usable materials;

d)         Damage caused by the wind.

* : The threats indicated are listed in alphabetical order; their order does not constitute a classification according to the importance of their impact on the property.
Furthermore, they are presented irrespective of the type of threat faced by the property, i.e. with specific and proven imminent danger (“ascertained danger”) or with threats which could have deleterious effects on the property’s Outstanding Universal Value (“potential danger”).

** : All mission reports are not always available electronically.