Site Minier de Plombières

Site Minier de Plombières is a former mining and smelting complex in Montzen, part of the municipality of Plombières in eastern Belgium, where zinc and lead ores were extracted and processed from the 14th century until 1922. The location was historically known as Bleyberg, a name it carried until it was officially changed on September 20, 1919. At its peak, the mine ranked as the most important lead deposit in eastern Belgium and the third-largest source of zinc in the region.

How did mining begin at this site?

Traces of ore extraction in the area date back to the Middle Ages, when local miners focused primarily on lead, with zinc recovered only as a by-product. A turning point came in the early 19th century when the Cockerill brothers, members of a prominent industrialist family behind much of Belgium's metallurgical development, applied for the concession to work the Bleyberg deposits. The Dutch authorities granted them permission to conduct exploratory research, and the municipality of Montzen formally approved the request on June 23, 1825. A few years later, in 1828, the Cockerill brothers secured the full concession for the Bleyberg lead mines, paving the way for a much larger industrial operation.

What did the Bleyberg complex look like at its height?

From 1845 the mine reached full production, and the following year the operation was restructured into a joint-stock company, the Compagnie des Mines et Fonderies du Bleyberg, capitalized at 4.5 million Belgian francs. The site grew to include a large smelting plant with separate furnaces for lead and zinc: zinc ores were roasted in local shaft furnaces on-site and then reduced with coal to produce metallic zinc. The complex therefore combined the full industrial cycle — extraction, roasting, and smelting — under one operation. Its most prosperous years fell between 1856 and 1882, when it stood among the leading non-ferrous metal producers in the region. Mining continued without interruption until 1922, when both the mine and the smelter were permanently closed.

What remains of the mining site today?

After industrial activity ceased, the site gradually turned into a nature reserve, best known today for its calamine grasslands — a distinctive type of vegetation that developed because of the high concentration of zinc and other heavy metals left in the soil by centuries of mining and smelting. These unusual habitats now support specialized plant and animal species adapted to metal-rich ground, making the area notable for both its industrial history and its ecology.

Where can visitors learn about the site's history?

A house dating from 1645 still stands on the grounds of the former mining complex. Its ground floor now hosts an interpretation center covering the history of Plombières and its nature reserve, along with a tourist information point. Admission is free, pets are welcome, and a typical visit takes between 30 and 45 minutes. The site is reachable by TEC bus line 710 from Welkenraedt train station, a journey of about 22 minutes, and parking is available nearby for visitors arriving by car.

Frequently asked questions

What was the Site Minier de Plombières? A former mining and smelting complex in Montzen where zinc and lead ores were extracted and processed from the 14th century until 1922, previously known as Bleyberg.

Who developed the mine in the 19th century? The Cockerill brothers, who obtained the concession for the Bleyberg deposits in the 1820s and turned it into a large industrial operation under the Compagnie des Mines et Fonderies du Bleyberg.

What can visitors see there today? A nature reserve featuring distinctive calamine grasslands, plus a 1645 house that now houses an interpretation center and tourist information point, both free to enter.

How do you get there? By TEC bus line 710 from Welkenraedt station (about 22 minutes), or by car — parking is available near the site.