In response to today's environmental, political, economic, and social challenges, material experimentation in architecture invites us to recognize the importance of researching and analyzing the properties of construction elements, and to understand the role of spatial design and its immediate surroundings. While various textiles, plastics, and even waste from different sources are being recycled and given a new life, the debate around the use of salt as a building material encourages the development of more sustainable practices to reduce the industry’s impact on the environment, as well as to explore the renewed life of discarded minerals and mining waste for implementation in architecture.
The potential of salt acknowledges, beyond its life-sustaining qualities, a range of physical, mechanical, and aesthetic properties. As Valeria Montjoy explains, salt is affordable, antibacterial, fire-resistant, capable of storing moisture and heat, and reflects and diffuses light. However, it also presents challenges that limit its use as a building material, such as its tendency to absorb moisture, its susceptibility to wind and water erosion, and the fact that it can cause corrosion in metallic construction components.
Throughout history, numerous researchers, architects, and designers have explored the use of salt as a construction material in various regions of the world. Located on the Uyuni Salt Flat, in southwestern Bolivia, the Palacio de la Sal represents the first hotel built with salt blocks, completed in 1998. More recently, the proposal by the team of CHS+R arquitectos + Carlos Montes has aimed to develop the La Sal Pavilion as a tool for social transformation in public space.
In conversation with Mále Uribe, a Chilean architect, artist, and researcher, we set out to explore the processes and ideas she works on at the intersection of art, spatial design, and materials. Holding a master’s degree in Information Experience Design from the Royal College of Art, she seeks to communicate ideas about material culture and productive landscapes, rethinking, for example, mineral life. From sculpture to surface design, interior spaces, and multimedia installations, she focuses on experimental materialities, Salt Imaginaries being one of the many installations she has developed that explores a new perception of salt.
ArchDaily (Agustina Iñiguez): What does it mean to rethink mineral life? Why can materials be considered cultural constructions?
Mále Uribe: Rethinking mineral life is something I began to explore in an essay in 2019, driven by a desire to rediscover the inherent value and legacy of the minerals that shape the territory, in order to open up a critique of contemporary extractivist dynamics that reduce the potential of natural resources to their technological and economic value. This rethinking involves remembering that minerals belong to much broader and more complex systems of value than the natural worth attributed to them by the sciences at different historical moments. They are not only part of local cultures, but are also the very origin of the territory’s evolution and its particular geography – that is, they are not passive and inert entities, but autonomous and active ones, with an incredible transformative capacity within the slow evolutionary scale of geological time. Rethinking mineral life means shifting our gaze to a different speed and a different focal point, where we begin to value their material agency.
In practical terms, the importance of this lies in the fact that by focusing solely on the economic value defined by technological industries, we ignore and disregard most of the material processed during extraction. For example, in copper extraction and the large-scale movement of matter involved in its processing, only 3% becomes copper concentrate, while the rest is either discarded or at least changes its state and location. Lithium, found in the brines of Atacama –home to the world’s highest concentration of aqueous lithium– has a concentration below 2%; the rest is water and salts that evaporate and are discarded as waste. These figures reveal that mineral extraction is radically inefficient in terms of material optimization, as most of the matter becomes invisible. Decades ago, attention was focused on saltpeter for the production of gunpowder and fertilizers, until synthetic saltpeter was invented. Today, the focus is on lithium as a key element in the global energy transition. Thus, the value of minerals shifts radically according to the technological and cultural changes taking place in different parts of the world, and our perception of mineral life is shaped by that demand. This is why I believe it is crucial not to forget the importance of the narratives we construct around our resources, and I believe that art, design, and architecture can play a significant role in that process.
Rethinking mineral life from a multidisciplinary approach is, for me, a way to connect different worlds and to examine matter through its poetic, symbolic, and local cultural imaginary, seeking to understand the various forms of value and heritage that these minerals imprint on the landscape more holistically. - Mále Uribe
This also invites us to revisit the work of local communities with stone, small-scale mining, craftsmanship, and other forms of engagement with minerals. On another level, this rethinking is also an invitation to revalue the desert: to stop seeing it as an inert terrain where the waste and stockpiles of various industries accumulate, and instead recognize it as an active and transformative land, one that deserves proper care and respect as a landscape.
AD: What sparked your interest in researching materials and extraction processes in the Atacama Desert in Chile?
MU: My interest in mineral matters emerged from a line of inquiry that was more philosophical than material. While studying for my Master’s at the RCA in London, I read many new materialist theorists and began approaching a new understanding of the material world, one that describes materials as active agencies. I wrote my thesis on Karen Barad’s agential realism and her concept of intra-action, and I explored the writings of Latour, Jane Bennett, and others, though I still wasn’t entirely sure how the concept of “material agency” would translate into my practice. But during a trip to the desert, I visited salt flats and saline formations that led me to reinterpret all these concepts, now clearly illustrated before me in salt’s ability to crystallize and transform, even while being an “inert” substance. This discovery sparked a desire to rediscover salt and its different agencies in the desert, so I submitted a proposal to the Design Museum’s residency program in 2019 in London. Winning that residency was a turning point that allowed me to research these topics, take new field trips, and confront the extractive world and the vast masses of seemingly inert mineral waste that stand in contrast to the idea of mineral agency. From that point on, my work turned toward exploring the distances and tensions between these two opposing mineral realities: agency and waste.
AD: How can discarded minerals and mining waste contribute to more sustainable architectural solutions?
MU: The lithium and copper industries, those that position us as the world’s largest exporters of these materials, generate thousands of tons of material waste every year. In Chile, there are more than 750 copper tailings, most of them with little information about their composition or history. The discarded salts from lithium ponds, on the other hand, also remain largely undocumented; their composition isn’t directly toxic, but I have personally witnessed the incredible transformation of the landscape over the last decade, tons of salts decanted that were once dissolved in underground brines and their extremophile microbial ecosystems.
I believe that minerals are never waste, rather, we position them as waste, returning to the idea of cultural construction. Their natural properties still exist, even after we have processed them. - Mále Uribe
Architecture and construction industries, meanwhile, require stone, gravel, rock dust, additives, and countless other mineral supplies that are often extracted specifically for this purpose from different locations, through extractive processes that also cause sedimentary imbalances, erosion, and, frequently, the destruction of fluvial morphologies such as rivers and coastlines. Yet mining already generates tons of sand and displaced materials that should be used for these ends, rather than being turned into hidden dumps or tailings with unbalanced material compositions. These discarded sands and gravels could meet many of the needs of materials engineering in architecture and other uses, whether as replacements for aggregates and additives in concrete, as clay-like substances, or as new materials transformed through heat or chemical activation, such as geopolymers. In the Salt Imaginaries project, I proposed several paths for reusing discarded salts, while in collaboration with T2CM at the Pontificia Universidad Católica de Chile, we have been exploring alternatives for copper tailings through both artistic outcomes and architectural applications. They have an excellent track record processing mining tailings for the construction industry through various methods, some of which even improve the mechanical strength of concrete.
If we were able to systematize these potential material uses to some extent as part of extractive processes, we could optimize and reduce the amount of mining waste, monitor its composition and distribution, detoxify contaminated tailings, and protect the human and non-human communities that inhabit the affected areas. Given that mining handles such massive quantities of matter, it is urgent to think about how we can implement systems that ensure sustainable material life cycles. But I believe it is essential that this be approached from a multidisciplinary perspective, one that can also shift the perception of these materials, which are often associated with something negative.
AD: Why did you choose to investigate the use of salt, and what are its possible applications?
MU: Salt is a highly abundant material on the Earth’s surface, and it has had many uses due to its versatile chemical properties. In the desert, different types of saline minerals have had multiple historical roles with major impact on the country’s mining history. But salt has also been used locally as a construction material, with salt rocks and mineral gypsum used in extremely arid environments. Considering the large quantities of salt that are discarded in salt mines or in the evaporation ponds of lithium extraction, I found it important to revisit what forms of vernacular construction could incorporate this abundance as a raw material. At the same time, it seemed relevant to highlight the many forms of value that salt holds in the desert, and to raise awareness about the material issues associated with lithium extraction, where salts are part of a fragile water and microbial ecosystem. I’ve been working with crystallizations for years because I find them fascinating, as a visible proof of mineral autonomy and of the long geological past of the water reserves tied to these landscapes.
Salts are challenging materials in terms of their applications as construction materials, since they interact rapidly with atmospheric conditions. They have the incredible ability to crystallize, that is, to grow and structure themselves autonomously. - Mále Uribe
Depending on their composition or interaction with the environment, salts can expand into diverse crystalline structures. This capacity opens up an excellent pathway for collaborative construction with nature, one that uses sunlight and the environment as the main resource, allowing the surface to self-organize under its own logics with great efficiency. At the same time, however, salt is hygroscopic – it absorbs water. In fact, some salts discarded in the lithium ponds of the Salar de Atacama have deliquescent properties, meaning they can dissolve in the water they absorb from the air. This characteristic poses challenges when considering the durability of architectural applications in more humid environments outside the desert. For this reason, it is a material that first and foremost invites us to think locally.
In the Salt Imaginaries project, I explored both crystallization and other methodologies such as agglomeration, compaction, heat, and chemical reactions to create murals, sculptures, experimental structures, and tiles for architectural applications. What’s interesting about crystallization is that I was able to carry it out naturally on site within the lithium ponds, capturing the salts before they became waste and were piled into salt cakes. Last year, we created a series of crystallized modules and systems in collaboration with NOT (No Ordinary Things) to build a large structure in the desert, but sometimes it's difficult to bring these projects to completion due to lack of funding or the absence of collaboration from mining companies that provide materials and infrastructure. Salt Imaginaries remains an ongoing project with different methodologies, slowly progressing toward new horizons. It has been exhibited in its various stages at the Design Museum (London), Galería Gallo (Santiago), Palacio Pereira (Santiago), CAFA Art Museum (Beijing), and the Science Museum (Hong Kong).
AD: What other materials could undergo similar processes and applications in architecture? What research projects are you currently working on?
MU: I’ve had the opportunity to research other forms of mineral waste, and there are always hidden processes and narratives. In 2021, I did an art residency in Portugal, in Barreiro, a former abandoned industrial park. Among the many types of waste found there, I came across ashes and pyrite discards with an intense purple color, from which a pigment known as Caput Mortuum is extracted, a pigment used since the Renaissance. Its name comes from Alchemy and refers to the black residue left at the bottom of a flask after distilling or calcining a substance. It was what couldn’t be transformed into anything valuable, a slag with no possible worth. I purified it by hand and used it as a pigment and as a substitute for aggregate in cement-based mixtures for sculptures and artworks. The project remains on hold pending future funding, as scientific collaboration is required to process the heavy metals that are toxic to human health. Even so, it stands as an example of how many areas of mineral or industrial waste, often environmental and community hazards, could shift in value or use if we dig deeper into their histories and their physical, mechanical, and aesthetic properties. In many cases, not much science or funding is even needed, as these are simply piles of sand without toxic content.
I am currently developing the project Minerasophia, a long-term research initiative that looks at the mineral world more globally and explores its “wisdom” (sophia, from the Greek) - that is, its various forms of legacy and value. It is a project that proposes weaving together two dimensions of mineral study: one more poetic, focused on admiring its geological agency and value as cultural legacy, and another more scientific, aimed at reshaping its perceived value by collaborating with science and the mining sector to re-signify minerals that have lost their worth due to human interventions. This research has opened up new forms of collaboration with artisans and local stonemasons, working with sculpted stones and the waste and discards produced through these small- and medium-scale practices. Various stages branch out from this project; the first was the art exhibition of the same name that I held with Collectio gallery in March 2025, which featured a series of 22 sculptures made with stones, crushed rock, and mining discards. Among them, the Alquimia series composed various sculptures in the form of "reconstituted stones," combining discarded mineral materials such as combarbalite and basalt with copper tailings and pigments, creating visual compositions in new forms of value. This project opened up a beautiful investigation into the communities and landscapes shaped by craftsmanship and mineral extraction.
In that same process, a project emerged in London with Maredia, the new Chilean restaurant in the city, for which I carried out territorial research and created a mural as cladding, made from rock dust discarded from Combarbalita in collaboration with local artisans, and copper tailings in collaboration with T2CM at the Pontificia Universidad Católica. The project fabrication was done in collaboration with Cromolux and Grava. In addition, we also inaugurated the Chilean Pavilion at the London Design Biennale, titled Minerasophia: Underground Cycles, developed in collaboration with the renowned Chilean designer Constanza Gaggero and producer Juan Pablo Vergara. The pavilion served as a showcase for the full theoretical and research depth behind the project. Being framed within a design context, it allowed for the expansion of new narratives through display cases, texts, sculptures, material samples made from mining waste, along with a large central audiovisual piece combining historical archive footage, animations, and documentary recordings.
From here, more projects will continue to emerge, both in the artistic and exhibition realm as well as in the technological and material development field. Minerasophia will keep moving across disciplines in an effort to find new formats, audiences, and media to experiment not only with mineral materials themselves, but also with the narratives that are constructed around them.
This article is part of the ArchDaily Topics: Rethinking Materials: Techniques, Applications and Lifecycle, proudly presented by Sto.
Sto sponsors this topic to emphasize the importance of digitized materials in architectural design. Its high-quality PBR-files, as demonstrated in a case study with the London-based architecture firm You+Pea, provide architects with precise tools for confident decision-making from concept to execution. This approach bridges virtual and physical realms, supporting more accurate and efficient design.
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