However, the factory closed abruptly in 1984, leaving its interior workshops frozen in time, due to fierce competition from Asian markets and the progressive relocation of valley industries to more accessible plains near highway exits.

[6] During the 17th century, the valley's products were exported to various countries, including Spain, Italy, Germany, Turkey, and India, reflecting the global reach of the cutlery industry.

[12] The narrowness of the Durolle gorges led to the relatively small size of the factory, which often collaborated with other paper mills in the valley to fulfill large orders.

[11] Consequently, Thiers experienced a decline in competitiveness, ultimately leading to the permanent closure of the paper mill at the Forges Mondière site in the mid-19th century.

[12][10] Following the closure of the paper mill in the 1880s, the premises underwent a transition in function, becoming a site for cutlery production, a practice that was soon accompanied by the establishment of a sawmill.

The Forges Mondière gained recognition for the quality of its products, and its reputation rapidly expanded beyond the Auvergne region, attracting prestigious clients such as Christofle, Colliot, and Caput.

"[6] Beginning in the second half of the 20th century, the factory and its workshops underwent further modernization, and the Durolle River was no longer used as an energy source, having been replaced by electricity.

[9] Canadian artist George Trakas examined the history of the Vallée des Usines through his art and installed the "sword bridge" along with a series of walkways that still overlook the waterfall and the Durolle torrent.

The entire site, inclusive of the interior features such as manufacturing machines and hydraulic turbines, was officially registered by decree on June 14 of that year.

Following several months of efforts to render the structure watertight, the city arrived at the decision to undertake a complete demolition of the roof, in anticipation of its replacement.

In response, the municipal authorities took measures to secure the building with support beams, while also initiating the process of planning for future restoration efforts.

[24] Since 1984, the city of Thiers has conducted studies to rehabilitate the Forges Mondière and transform the site into a branch of the Museum of Cutlery, focusing particularly on 20th-century industry.

[25] These changes initially took place at the economic level, marked by a reconversion and diversification of activities based on traditional trades such as mechanics, forging, and plastics processing.

However, the valley remained excluded from these revitalization efforts until the mid-1980s, when the Thiers municipality initiated discussions to breathe new life into an underappreciated industrial heritage.

The inclusion of an urban project was predicated on the valley's status as a significant land and real estate reserve close to the city center.

Notably, the Forges Mondière factory featured an innovative hydraulic energy exploitation system, which garnered significant attention for its advanced technology and sustainability.

[31][32] The municipal administration, elected in 2020, has proposed an ambitious program to revitalize the Vallée des Usines and the Forges Mondière, recognizing their significant tourism, economic, urban, cultural, and symbolic potential.

[33] By the end of December 2020, the municipal government of Thiers had declared its intention to "explore all available funding sources" to preserve the Forges Mondière building, emphasizing the potential for collaboration with the Heritage Foundation [fr].

[24] The primary structure is situated within the profound Vallée des Usines,[35] with rock formations encircling it in the posterior section, thereby serving as a natural barrier.

The roof, constructed in the shed style, features numerous wooden lanterns and encompasses the majority of the factory, with a minor portion employing a single-pitch design.

[35] An annex building, which formerly housed administrative offices, is located on the opposite side of the river[35] and can be accessed directly from Avenue Joseph-Claussat [fr] without crossing a bridge.

Drawing inspiration from the local topography, she directed her attention to the structures of the Vallée des Usines, with a particular emphasis on the Creux de l'Enfer, the May factory, and the Forges Mondière.

[38] The novel La Ville noire (1860) by George Sand features a section of the story set at the May factory, located adjacent to the Forges Mondière.

[39] In 2019, the pop group L'Impératrice filmed scenes for their music video, Là-haut, in front of two notable industrial sites: the Creux de l'Enfer and the May factory.