Home ] About us ] Alphabetical archive ] Archeology ] Author submission screen ] Book reviews ] Canoeing ] correspondents ] date archive ] East Midlands ] Economics ] Education ] Environment ] Feminisim ] Fresh ] Geology ] Health ] hit counts ] House swaps ] Jokes ] iLinks ] Love ] Media ] Obituaries ] Paleontology ] Past thoughts ] Politics ] Poetry ] Quotes ] Religion ] Sex ] Site Awards ] Smartertimes past ] Spain ] Trade Unions ]

You have reached  In December 2006 we moved to with faster servers and discussion boards.  Click here to follow us.  

Home ] Up ]

A well-managed environmental disaster

Aznalcollar is a mining town 40Km west of Seville.  

azalcollar map2.jpg (78895 bytes)    azalcollar map.gif (12051 bytes)

An open pit zinc mine had operated here for many years until it finally closed in 1996.  

However, an ore body with commercially retrievable levels of zinc, copper, lead and silver, had been discovered at Los Frailes one km to the east in 1988.  When the old mine was depleted the owners, the Swedish Canadian company Boliden, moved the mine equipment over.  The new mine produced 4 million tons of ore in 1997.   Here are two pictures of the Los Frailes mine pit.

frailes2.jpg (43834 bytes)    LosFrailes3.jpg (80683 bytes)

The ore was crushed and metals separated at a nearby treatment plant and the waste (the tailings) placed in two vast shallow ponds behind an artificial dam.  

los frailes dam map.jpg (67345 bytes)

On 25 April 1998 disaster struck.  The tailings dam wall failed and released about 5.5 million m³ of toxic tailings water and about 1.3 million m³ of semisolid waste. 

The pollution accident

The spillage was terrible.  The waste contained high levels of arsenic and many other toxic chemicals, and the liquid part threatened to reach Donana national park and cause tremendous damage to wild life. 

azalcollar map2.gif (126163 bytes)  los frailes dam break1.jpg (20114 bytes)  los frailes dam break2.jpg (44866 bytes)   los frailes dam break3.jpg (22675 bytes)  los frailes dam break5.jpg (110840 bytes)  los frailes dam break6.jpg (104652 bytes)

The clean up

Fortunately the clean up was rapid.  Boliden took charge of scraping up the solid waste that lay between the burst dam and the old Seville-Huelva road bridge near Sanlúcar la Mayor.  The government dealt with the area south of the road bridge.  

Boliden simply scraped up the solid waste and any contaminated earth, and placed it the old worked out Aznarcollar mine pit.   They managed to remove most of it before the winter rains so minimising the amount of heavy metal leached into the ground.  

The government contractors working downstream of Sanlúcar la Mayor also had to contend with toxic water running down the Guadiamar river and into Donana National Park.  They bulldozed low earth walls in the park and diverted the toxix run off into the Gualdaquivir river.  

The mine ceased operations temporarily after the accident.  It restarted in 1999, but experienced technical problems with the ore processing facility, and the operators decided to close it once and for all when the current pit was worked out in Sept 2001.  

The area today

I visited Aznalcollar in summer of 2006.  You can see the breach repair clearly.  

P8090099.JPG (874068 bytes)   P8090102.JPG (887811 bytes)  

The surrounding area is now a pretty bleak industrial park.

P8090100.JPG (917150 bytes)   P8090103.JPG (894212 bytes)  P8090105.JPG (888034 bytes)    P8090106.JPG (889664 bytes)   P8090107.JPG (888647 bytes)

Here is the dry bed of the Rio Agrio, which carried the pollution into the Rio Guadiamar

P8090104.JPG (870519 bytes)

But there is no pollution to be seen at the road bridge near Sanlúcar la Mayor.   Nor further downstream at the Roman bridge at Aznalczar.  Click here for August 2006 pictures.   

More importantly there is no visible damage in Donana.  These pictures below were taken in August 2006 at the site where the temporary earth dams were built to divert water into the Gualdalquivir.  The earthworks ran along the line of pylons.  

P8110211.JPG (915504 bytes)    P8110212.JPG (885666 bytes)    P8110213.JPG (912057 bytes)

The park is dry and barren but that is its normal state at the height of summer.  Chemical tests on the land indicate that there is no residual pollution.  

Here is a freighter running down the Gualdalquivir river from Seville to San Luca along the the edge of the park.

P8110205.JPG (927457 bytes)


Jim Thornton Nottingham Sept 2006



Home ] Up ]

You have reached  In December 2006 we moved to with faster servers and discussion boards.  Click here to follow us.  

Send mail to  with questions or comments about this web site.
Last modified: September 10, 2006