ISABEL RUBIO ARROYO | Tungsteno

The Salt Cathedral is undoubtedly one of the most remarkable places in Colombia. True to its name, it is constructed entirely from salt, but that’s only part of its allure. Situated 180 metres below the surface, it features a labyrinth of tunnels and massive salt-carved crosses.

In this piece, we explore the process behind its construction and uncover the secrets hidden within one of Colombia's greatest works of engineering, celebrated as the country's first wonder.

The spiritual refuge of miners

The Salt Cathedral is located in Zipaquirá, a picturesque mining town near the capital, Bogotá. To access the site, visitors pass through a long tunnel lined with eucalyptus logs and illuminated by green lights, adding to the mysterious atmosphere of the place. As you proceed, you enter a series of caverns and chambers adorned with majestic crosses carved in salt and illuminated by coloured lights that lend the space a mystical touch. The cathedral features three central naves symbolising the birth, life, and death and resurrection of Christ, along with an enormous basilica dome.

The indigenous Muisca people were the first to discover these salt deposits more than six centuries ago. Later, Spanish conquistadors arrived in search of El Dorado. "Instead of a city of gold, they discovered a city of salt," Luis Alfonso Rodríguez Valbuena, former mayor of Zipaquirá, told The Washington Post. In its early days, this cathedral was much more modest. Miners initially prayed in a small sanctuary built in the 1930s.

In this humble sanctuary, they prayed to the Virgin of the Rosary of Guasá, the patron saint of miners, seeking protection from toxic fumes, explosions, and the many dangers they faced daily while extracting tonnes of salt. “The work was very dangerous,” Juan Pablo García, the cathedral's administrator, told US broadcaster NPR, referring to the hazardous conditions in Zipaquirá’s salt mines, where commercial mining began in 1815. “Every day that they came out of the mine alive was a reason for giving thanks,” he added.

Access to the Zipaquirá Salt Cathedral is through a long tunnel lined with eucalyptus logs. Credit: Zipaquirá Salt Park

The underground reconstruction of a Colombian symbol

The first sanctuary was eventually closed due to instability, and the cathedral itself was shut down in 1992 after years of blasting, hammering and drilling caused structural problems. A public competition was held to replace it, and several proposals were received. The winning design came from Colombian architect Roswell Garabito Pearl, who designed a new church.

A team of more than 100 miners and sculptors was assembled to construct the new cathedral, which is located 200 feet (about 60 metres) below the original. One of the greatest challenges was moving the imposing rock salt altar from the old sanctuary to the new site, according to retired mining engineer Jorge Castelblanco, who was involved in the reconstruction. The altar weighed 16 tonnes and workers had to cut it into three pieces to transport it.

The Salt Cathedral is one of Colombia's most popular tourist destinations. Credit: Travel Life Experiences

Zipaquirá's underground jewel

The Salt Cathedral opened its doors in 1995. Guides often emphasise that everything inside is hand-carved, making it a true masterpiece of engineering and craftsmanship. Since 2024, it has also housed the Monumental Underground Museum 180. Nestled in the depths of this Colombian architectural marvel, the museum showcases 22 marble and stone sculptures crafted by national and international artists.

The crosses of the Salt Cathedral are hand-carved. Credit: Zipaquirá Salt Park

Over the years, the Salt Cathedral has become one of Colombia's most popular destinations for tourists and pilgrims alike, drawing more than 600,000 visitors annually. Although it is not part of the Seven Wonders of the World, it earned a place as one of the Seven Wonders of Colombia in 2007, receiving the highest number of votes in a national competition. Furthermore, in 2024, the Andean Parliament recognised it as a landmark of cultural, natural, and historical heritage within the Andean region.

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Sacyr has extensive experience in port and harbor construction that has now been transferred to the second phase of the Central Breakwater in the Expansion of the Port of Bilbao. With this project, Sacyr provides agile and sustainable construction solutions to culminate three decades of works in Bilbao's port area. 

Miguel Tejeda, Project manager, explains that the initiative stems from the growing demand for freight traffic at the port and the need to expand port facilities in the Pass due to the rezoning of port areas located upstream of the estuary for urban development purposes.

The Central Breakwater represents the final stage in the Expansion of the Port of Bilbao in the Outer Pass.

In the Summer of 2024, the Bilbao Port Authority awarded a joint venture, led by Sacyr Engineering and Infrastructure, the contract for this second phase. This phase encompasses a 310,000 sqm area and is scheduled to be completed within two years.

The project applies construction methods such as the use of reinforced concrete caissons and the development of a mass concrete superstructure, with an optimized design aimed at minimizing disruptions to existing port operations and maximizing the efficiency of the new quay. 
 

The floating dock comprises four towers and 16 ballast tanks, enabling the platform to be submerged to the desired depth. This allows for smooth formwork sliding and ensures the stability of the entire assembly. 

Additionally, the project includes the construction of 1,011 as an meters of new berthing docks: 664 meters for the new A3 Quay and 347 meters for the existing A4 Quay.

The caissons will be manufactured on-site using the Sacyr Uno floating dock.

The dock measures 56 meters in length, 36 meters in beam, and 15.9 meters in depth. During the process, the designed prop will be adjusted afloat, utilizing the naval stability of the caisson to optimize the slab construction for the subsequent caisson. 

The floating dock comprises four towers and 16 ballast tanks, enabling the platform to be submerged to the desired depth. This allows for smooth formwork sliding and ensures the stability of the entire assembly.

The main construction works include the fabrication of new concrete caissons and their subsequent filling with sand dredged from maritime deposits. Additional activities include constructing the breakwater, creating pier backs with land-based placement of riprap, executing the seaside and landside superstructures, extending the rainwater drainage network and installing port equipment.

The second phase will focus exclusively on building the vertical quay using reinforced concrete caissons topped with a mass concrete superstructure. 18 concrete caissons in total will be constructed using a floating platform or caisson-builder that facilitates continuous production.

Once completed, the caissons will be floated to their designated positions at the quay. They will be anchored by filling their cells with water until they sink to rest on the prepared foundation. Afterward, the cells will be filled with material, the joints will be sealed using concrete piping, and the gaps between the caissons will be filled with gravel.

Environmentally Friendly Construction

The project has undergone an Environmental Impact Assessment and has received the corresponding Environmental Impact Statement (EIS). It incorporates measures to mitigate turbidity during construction, such as the use of containment barriers and anti-turbidity curtains. Air quality and noise levels will also be closely monitored.

Furthermore, the filling material for the esplanade will be sourced from excavation surpluses from nearby projects.

The materials to fill the caissons will be extracted from a marine area parallel to the Petronor dike, located two miles off the coast to the north, spanning approximately 7.9 square kilometers.

Extensive Port Construction Experience

Sacyr has considerable expertise in port infrastructure projects, such as the extension of the Punta Sollana dock in the Port of Bilbao, the jetty at the Port of Langosteira in A Coruña, the protective works and Cruise Ship Dock at the North Extension of the Port of Valencia, the expansion of the Port of Garrucha (Almería), the fishing port of Blanes (Girona), and the Port of Marín.

Sacyr's maritime bases have allowed the company to develop many projects in the Azores Islands.

ISABEL RUBIO ARROYO | Tungsteno

Animal overpasses that keep wildlife safe, rail projects that use advanced hydroseeding and surplus soil management techniques to restore and enhance the landscape, and hospitals designed with natural materials that respect protected species are just a few examples of infrastructure projects that go beyond meeting human needs. These initiatives demonstrate a strong commitment to sustainability and integration with the natural environment.

A hospital that prioritises biodiversity

An example of environmentally conscious infrastructure is the Velindre Cancer Centre, developed by the Acorn consortium, made up of Sacyr, Kajima Partnerships and Aberdeen. The design of this cancer hospital, located in south-east Wales, prioritises sustainability by incorporating natural materials to reduce its carbon footprint and preserving least 60% of the surrounding land in its natural state. Efforts to protect local biodiversity include initiatives such as monitoring protected species. The facility will also feature solar and geothermal energy systems, and was honoured in the "Future Healthcare Design" category at the 2023 European Healthcare Design Awards.

This hospital is designed to minimise its carbon footprint and preserve biodiversity. Credit: Sacyr

Bridges that save lives

The Wildlife Crossing Project in Banff National Park, Canada, began in 1978 with the goal of reducing animal-vehicle collisions and restoring migratory routes disrupted by the Trans-Canada Highway. The first two animal overpasses were built in 1996 at a cost of $1.5 million each. The project now includes 38 underpasses and six overpasses that span the entire section of highway within the park.

These structures are designed to allow animals to cross the highway safely. In fact, they have reduced animal-vehicle collisions in the area by more than 80%—and by more than 96% for elk and deer, according to the Association of Professional Engineers and Geoscientists of Alberta (APEGA). Species such as grizzly bears, wolves, elk, moose and deer tend to favour overpasses, while cougars and black bears prefer the seclusion of underpasses. From a driver’s perspective, the overpasses look like typical highway bridges. However, as APEGA notes, "catch a glimpse of the top, and it’s clear they cater to a different crowd—the forest stretches from one side to the other, uninterrupted by the highway below."

This animal crossing aims to restore migratory routes and reduce collisions with vehicles. Credit: Parks Canada.

A railway project with a focus on the natural environment

Integrating infrastructure into the natural environment is becoming increasingly important in the development of sustainable projects. The Elorrio-Elorrio railway project in the Basque Country in northern Spain is an example of this approach. Developed by Sacyr Engineering and Infrastructures and Cavosa, in collaboration with Mariezcurrena, this 2.8 kilometre section of double-track platform is a key link in the high-speed railway line connecting three major cities in the region.

The project uses innovative techniques such as hydroseeding, which involves spraying seeds onto slopes and embankments to restore degraded landscapes while minimising the environmental impact. In addition, 850,000 cubic metres of surplus soil were relocated and used to create new embankments, improving the integration of the railway into the natural environment.

The project focuses on the development of the Elorrio-Elorrio high-speed rail section, which is part of the Vitoria-Bilbao-San Sebastián line. Credit: Sacyr

A dam that blends into the landscape

The Úzquiza dam, located in the Arlanzón river basin and managed by Sacyr Conservation, is one of the most modern pieces of infrastructure in the Duero region of Spain. The dam provides drinking water to the city of Burgos and nearby towns and was constructed using loose materials, with a minimum of concrete. According to Sacyr, this technique does not compromise the safety of the dam, while allowing vegetation to naturally integrate the dam into the environment: "The reservoir is so well integrated into the landscape that it could be mistaken for a mountain lake."

The Úzquiza dam was constructed using selected soils. Credit: Sacyr

It is vital that infrastructure is integrated into the environment to minimise its ecological impact and promote long-term sustainability. This helps to preserve biodiversity, reduce the fragmentation of natural habitats and avoid the destruction of local ecosystems, as these initiatives demonstrate. Environmental integration also reduces carbon footprints through the use of renewable energy and sustainable materials. This approach not only benefits the environment, but also promotes public acceptance by creating infrastructure that is in harmony with the natural landscape.

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Tungsteno es un laboratorio periodístico que explora la esencia de la innovación.

The top five best cities in responsible mobility in 2024 are Barcelona, L'Hospitalet de Llobregat, Bilbao, Madrid and Valencia, according to PONS Mobility, a consultancy firm specializing in strategic public and private management in responsible mobility and Meep, a digital platform that integrates and connects different transport services by creating sustainable connected mobility ecosystems.

These organizations have published the first ranking of the top 20 most sustainable and safest cities among the main Spanish cities by population, according to data from the INE.

To distinguish whether a city has responsible mobility, this ranking considers governance, modal shift, electrification, and safe mobility.

The report by Meep and PONS Mobility has analyzed up to thirteen key indicators to generate an accurate assessment of each city in relation to its situation, divided into four subgroups to group the set of indicators obtained: governance of Low Emission Zones (LEZs), electrification of the car fleet, modal shift and safe mobility. 

The success of the best-ranked cities has been based on three key pillars identified:

• The coordinated implementation of infrastructures and services, evidenced by the correlation between the density of bike lanes and the use of public transport.
• The efficient use of available aid, with an average execution of 85% of the Recovery Plan funds in the three main categories.
• Digitalization as an integrating element, which has made it possible to reduce waiting times by 24% and increase public transport travel time accuracy to 92%.

Data shows a direct correlation between high scores in this ranking and three fundamental factors: the implementation of low emission zones, transport electrification and the degree of digitalization of mobility services. 

These are the main measures that the best-positioned cities have implemented:

• Barcelona has taken risky decisions in the regulatory field. It has the largest area with low emissions, with complete electrification in its public transport fleet and leadership in terms of charging infrastructures.
• L'Hospitalet stands out for having the lowest percentage of vehicles without an environmental label, only 19%, and a public transport network that serves 82% of its population. 
• Bilbao has managed to transform its urban core with more than 4 kilometers of pedestrian streets per 100,000 inhabitants, the highest ratio among the cities studied, creating an environment that prioritizes pedestrians and significantly reduces emissions in the city center.
• Madrid has managed to electrify 63% of its public transport fleet, one of the highest percentages in the study and has implemented a digital traffic management system that has reduced waiting times by 24%.
• Valencia leads the modal shift, encouraging citizens to seek more sustainable transport options instead of private vehicles.

Future trends

• The modal shift involves infrastructure.

• Pedestrianization of streets towards the 15-minute city concept.

• Electrification of transport fleets with enough charging points.

• Urban toll and digitalization, as is the case in London, Paris, Los Angeles, Paris, cities where parking is charged or access through an access control system according to its volume.

• Speed reduction in urban traffic.

• Reduction of surface parking:  it could be for bicycles and pedestrians.

• Integration of certain means of payment in transport through the implementation of the digital economy. Promotion of sustainable and safe transport.

• More electrification posts, there are already 40,000 charging stations in Madrid.

ISABEL RUBIO ARROYO | Tungsteno

Rem Koolhaas worked as a journalist before becoming an architect. Known for his provocative style, he went on to become one of the world's most influential architects. So much so that he was awarded the prestigious Pritzker Prize in 2000. His most famous works include the headquarters of China Central Television in Beijing and the Prada Foundation in Milan. But he is most famous for his book Delirious New York: A Retroactive Manifesto for Manhattan, which outlines his perspective on the chaos and vitality of this city.

The book that catapulted Koolhaas to fame

Koolhaas' writings made him famous in the field of architecture before he had completed a single building, as the organisers of the Pritzker Prize note. The Rotterdam-born architect, who spent four years of his youth in Indonesia, was a journalist in the 1960s. After graduating from the London School of Architecture Association in 1972, he received a scholarship to travel and research in the United States. It was there that he wrote Delirious New York, hailed by critics as a classic text on modern architecture and society.

In this book, Koolhaas examines New York as a metaphor for the diversity of human behaviour. In the late 19th century, the explosion of population, technology and information transformed Manhattan into a laboratory for the invention and testing of a new way of life: the culture of congestion. This culture, he says, is reflected in the city's architecture. "Manhattan," writes Koolhass, "is the 20th century’s Rosetta Stone… occupied by architectural mutations (Central Park, the Skyscraper), utopian fragments (Rockefeller Center, the UN Building) and irrational phenomena (Radio City Music Hall)…"

New York City today is a metropolis full of contrasts. Credit: Pxhere

The Chrysler Building sleeps with the Empire State Building

The iconic cover image of the first edition of this book shows the Empire State Building and the Chrysler Building lying in the same bed. This symbolic image captures the essence of the architect's approach to New York City, presenting a provocative and playful vision of architecture and urbanism. When Koolhaas wrote it, the city was in a spiral of violence and decay. But he saw it as a potential urban paradise. "It was geared against this idea of New York as a hopeless case," Koolhaas told Smithsonian magazine. "The more implausible it seemed to be defending it, the more exciting it was to write about."

The book explores in depth the chaos and complexity of New York as a constantly evolving metropolis. Although the first skyscrapers were built in Chicago, Koolhaas argues that New York became the true epicentre of urban modernity. Some critics have accused the architect of celebrating Manhattan’s congestion and lack of urban planning. His defenders argue that his analysis seeks to highlight the complexity and vitality of urban life. Today, Koolhaas' view of New York has changed. "I no longer see New York as a physical reality, but as the epicentre of certain values that I don't feel at all close to," he told Icon Design in 2023.

The architect's legacy

In 1975, Koolhaas founded the Office for Metropolitan Architecture (OMA) in London, a practice that focused on contemporary design. The firm won a competition to expand the parliament building in The Hague and a major commission to develop a master plan for a residential district in Amsterdam. Years later, the architect was commissioned to design and build the Netherlands Dance Theatre.

His most iconic works include the Austrian House, the Taipei Performing Arts Centre, the Qatar National Library and Qatar Foundation Headquarters, the Galeries Lafayette Foundation in Paris, the Prada Foundation in Milan, the China Central Television Headquarters in Beijing and the Seattle Central Library. He also published the mammoth book S, M, L, XL in 1995. In it, he summarised OMA's work in what he called a "novel about architecture," which includes thoughts, plans, photographs, essays and writings of fiction.

The headquarters of China Central Television in Beijing is the work of architects Rem Koolhaas and Ole Scheeren. Credit: Wikimedia Commons

Despite the success of Delirious New York and his long career as an architect, Koolhass, 79, says he has never had it easy: "We have never been able to turn clients away. We've never had that moment of guaranteed peace of mind. And I think it's because, as well as bringing an interest in architecture, we were at the same time imparting criticism, which made our approach less attractive to many clients. We probably scared off as many as we attracted," he says.

Tungsteno is a journalism laboratory to scan the essence of innovation.

In January of this year, the Community of Madrid approved the Cognitive Hospital project, a platform designed for the comprehensive management of hospital infrastructure. 

Sacyr leads the consortium developing this project, which includes participation from Sener Mobility, Fracttal, Cuatro Digital, Open Ingenius, Áptica, and the technology centers of Tecnalia, UPM, and CSIC.

We are already working on developing innovative pilot projects utilizing new technologies such as Artificial Intelligence (AI), IoT, advanced algorithms, 7D BIM, Big Data, and more to transform hospital management. 

Sacyr has developed a smart platform that optimizes the building's operation and maintenance processes. Its implementation enhances energy efficiency and improves the air quality within the hospital.

Additionally, a digital twin based on the hospital's BIM model has been developed and will be integrated with the cognitive platform, enabling predictive maintenance.

Furthermore, through augmented reality, it will be possible to obtain information from any hospital facility and system, facilitating building maintenance tasks. 

Additionally, through the use of LiDAR sensors and AI algorithms, alerts will be generated to detect queue formation, aiming to reduce waiting times and improve patient care.

Sener, using artificial intelligence, processes different types of data to predict thermal behavior and the risk of disease transmission through air and water. The system will automatically adjust equipment operation to improve the quality of life for patients and healthcare workers while minimizing energy consumption. 

Fracttal geolocates the strategic assets of hospitals in real time, significantly reducing the search times for healthcare personnel. Its technology enables detailed control over the status, maintenance, and availability of each asset.
Open Ingenius, using virtual reality, creates environments for continuous staff training on occupational risks and emergencies, without disrupting hospital operations or compromising user care quality. 

Cuatro Digital leverages blockchain technology to ensure circularity by certifying the accuracy, accessibility, and transparency of data. It will collect data on construction materials, energy consumption, and CO2 emissions.

Aptica is deploying a new multi-technology communications network throughout the hospital to support all use cases. The result will be a robust and stable network that allows comprehensive connectivity across sensors, systems, and equipment, facilitating daily hospital operations.

European Funding

The Cognitive Hospital project (file no. 59/178676.9/23) is co-financed by the European Regional Development Fund as part of the ERDF operational program of the Community of Madrid for the period 2021-2027. Implementation will take place at Hospital del Henares (Coslada, Madrid), managed by Sacyr, over a period of three years (2024-2027).

This ambitious project has a budget of €6.1 million, including a €2.9 million grant from the Community of Madrid. These funds are part of the 2023 grant call to enhance public-private cooperation in R&D&I through projects with a significant "tractor" effect.

At the moment, all sludge generated from Sacyr’s wastewater treatment plants in Chile is transported to a sanitary landfill. 

“Sacyr Water in Chile has turned this challenge into a solution that aims to boost the value of this waste 100% by developing a nutritionally and biologically enriched product through the incorporation of phosphate-solubilising microorganisms, struvite, and other mineral sources that serve as fertiliser for agriculture”, explains Ricardo Herrera, Technical Manager of Sacyr Water in Chile and LodoVerde Project Head. 

Laboratory trials are currently underway at the Curauma Biotech Core (Núcleo Biotecnología Curauma, “NBC”), a branch of the Pontificia Universidad Católica de Valparaíso, wherein the sludge passes through a laboratory-scale anaerobic digester and a fluidised bed reactor for the production of  struvite. 

“The project will last roughly two years, beginning with an initial phase in the lab, where actual conditions are simulated, and concluding with the implementation of the results obtained. Partner entities will provide support throughout the process, allowing us to take all the sludge generated at our plants to market as agricultural fertiliser. To achieve this, we rely on collaboration from the supplier Abonos San Francisco”, says Etienne Valdés, R&D Analyst for Sacyr Chile’s Innovation Department.  

The idea is to treat as much as 8,000 tonnes of enriched sludge annually and bring it to market by the end of December 2026, which will increase crop productivity by 20% and promote environmental sustainability through more sustainable waste management practices.  

Concrete is the most durable, versatile, and accessible material for construction, but it is also one of the most polluting, as its manufacturing process generates significant CO₂ emissions.

For this reason, Sacyr Engineering and Infrastructure is seeking innovative solutions to mitigate these environmental impacts, a goal achieved with the B-LOW2 project: “Eco-sustainable Cement-Based Materials that Reduce Our Carbon Footprint.” This initiative eliminates one of the most polluting components in concrete production: clinker.

This project is funded by the Ministry of Science, Innovation, and Universities, through the State Research Agency under the call for “Public-Private Collaboration Projects.”

Clinker is responsible for 65% of CO₂ emissions in concrete production. This project explores how to eliminate it and replace it with other sustainable materials that meet the performance standards required by current regulations.

The European Commission has set the goal of achieving carbon neutrality by 2050, positioning the Spanish cement industry as a key player in this ecological transition. B-LOW2 project aligns with the policies of the “European Green Deal” and the “2030 Agenda,” promoting circular economy principles and the use of recycled materials.

In this project, sustainable resources derived from waste will be used to reduce clinker and conventional aggregates, enabling the development of both structural and non-structural concretes as well as special mortars. This approach aims not only to cut CO₂ emissions but also to limit the consumption of natural resources.

The materials selected to replace clinker include construction and demolition waste (C&D waste), biomass, stainless steel slag, and kaolinite.
This initiative is driven by the Innovation and Operations Departments at Sacyr Engineering and Infrastructure, in collaboration with Grupo Puma and the Universities of Córdoba and Granada.

Additionally, Sacyr Engineering and Infrastructure is researching other types of sustainable concretes, currently under development in pilot projects.

Other Developments in Sustainable Concrete

This is not Sacyr’s first venture into sustainable concretes. In collaboration with Flexofibers, Sacyr Engineering and Infrastructure developed new concrete reinforcement fibers that replace traditional steel reinforcements with materials derived from end-of-life tires (ELTs). The first application was for a slope outside the Zumelegi tunnel in Elorrio (Vizcaya). These concretes, certified by the Torroja Institute of Construction Science, foster circular economy practices within the sector.

In addition, Sacyr Chile has developed a new type of concrete using recovered glass waste sourced from major cities such as Santiago and Valparaíso to reduce the proportion of cement content in the material.
Glass contributes an average of 13.4% increased mechanical strength in concrete after 28 days, enhancing durability.

Thanks to its fire-resistant, inert, pozzolanic properties and amorphous atomic structure, glass has various industrial applications, such as urban furniture, 3D printing, and radiation shielding in nuclear facilities.

This innovative concrete contains reduced cement content, water, aggregates, and powdered glass. Currently, the glass powder—provisionally named WG-X—is prepared through various processes including selection, control, crushing, and measurement.

Road infrastructure needs to adapt to the changes made by vehicle manufacturers, both for private and professional use.

According to Marta Gil, Sacyr's Chief Strategy, Innovation and Sustainability Officer, in the future, innovations in connected vehicles and roads will go hand in hand, and "that future consists of providing cars with more technology and on-the-road connectivity, with the incorporation of technology to make these infrastructures smarter and safer, not only for drivers and road users, but also to improve the occupational safety of employees."

Currently, the most booming mobility market trends are autonomous mobility, connected vehicles, and generative artificial intelligence.
A driverless car or bus requires systems that increase road safety, hence Sacyr's interest in learning what the needs of both public customers and the manufacturers of these vehicles are in order to adapt our works and maintenance work, as well as the roads we operate towards more connected mobility.

The second edition of InnoVision, held on November 27 at Sacyr, addressed the challenges and opportunities of connected mobility, paying special attention to regulation in the sector and to learn about real cases of how the most cutting-edge technologies on the market are being implemented.

Right now, we are working on the Sustainable Mobility Law, which aims to guarantee governance and coordination at all levels and thus guarantee mobility as a right. Mobility has to be accessible, inclusive and universal.

In addition, the Ministry of Transport and Sustainable Mobility is working on a technological platform to learn driving speeds, their origin and destination on the national road network, the road surface, etc., also with the aim of digitizing processes and avoiding the problem of road safety.

As for Spain’s Directorate General of Traffic, work is being done on a new regulatory framework on vehicles through the modification of the general vehicle regulations.

This entity launched the DGT 3.0 project, in which Sacyr participates, which seeks to find greater safety in employees who work on the roads, with digitized connected cones to show where the works are, also with IoT vests to detect workers on the construction sites, with the aim of giving the citizen as much information as possible.

Likewise, the Madrid City Council is also working on tools that allow drivers to group data to learn driving patterns and thus be able to plan a more controlled mobility. Through big data, it has estimated that 14 million trips occur every day, taking all forms of mobility into account. According to data from the City Council, sustainable mobility has increased, especially in public transport. In addition, 4 million people walk every day. AI allows to see how people move.

Technologies that make a difference

On the same day, specific examples were presented of how progress is being made in the deployment of technological solutions that will allow connected roads to develop their full potential.

This is precisely the objective of the MOVINN innovation ecosystem promoted by Sacyr together with such relevant players in the sector as Renault Group, CTAG, CIDAUT, ITENE, Sernauto, ITS Spain and Pons Mobility, to strengthen collaboration between the entire value chain and promote the development and adoption of these innovations. Among them, some such as: 

-Frontier Project (Factual): It has developed the Smart Roat Index, with a collection of 56 technical attributes classified into three blocks to define technical indicators that allow characterizing an infrastructure rating for autonomous cars: physical, digital and connectivity infrastructure. Its purpose is to preserve the safety of mobility with the aim of studying how autonomous cars are mixed with normal vehicles in infrastructures in a safe way.

-Tecnalia: Connects cameras with drones to capture information on possible risks for workers. It also works with the teleoperation of machinery or vehicles in tedious and repetitive operations within the sector. 

-Valerann: He works to increase road safety through data with the help of artificial intelligence, so that it is understandable and actionable by the operator. How to add value to a road so that autonomous cars go in a safe way so that the car user goes without executing any driving-related actions. 

-Renault, its main objective is safety. They have the Human First program, a system for the driver to identify how they have driven through a score they receive, with the safety code, to improve driving at the moment, or what the braking system is like, measured with the Safety Guard. In its transformation from a company that manufactures cars to a service and technology company, the Renault group is clearly committed to collaboration and open innovation, underlining the importance of coordinating the information currently collected by vehicles with that which companies such as Sacyr recover from the infrastructures they operate.

Plug & Play: The world's largest investor in startups has supported the development of the German technology company Klimator, which makes forecasts on current and future road weather for the entire road network. The company's forecasts allow drivers to connect to roadside weather sensors for real-time information and the winter service industry to make decisions about snow removal and snowmelt. The ability to integrate this technology into the car to increase road safety is being studied.

Understanding road-surface conditions is essential to performing proper maintenance that improves highway safety.  

Sacyr InRoad is an innovative initiative from Sacyr Conservation based on artificial intelligence. This award-winning technology continuously assesses the main markers and indices that gauge roadway conservation.  

With this project Sacyr Conservation won the AXA Award for Innovation and Development in Road Safety at the 14th annual “Ponle Freno” Awards, organised by Atresmedia.

Continuing the success of the prototype, Sacyr now unveils InRoad Evo. With help from the Plan to Support Sustainable and Digital Transport (Plan de Apoyo al Transporte Sostenible y Digital) to promote industrialisation processes, the project has been scaled up through the manufacture of 11 devices that include improvements to new inclination and temperature sensors to help optimise the algorithm and yield more precise results.  

“The project features two technologies: one that analyses the road surface and another that assists in interpreting the results”, explains  Alejandro Otero, Innovation Project Manager for Sacyr’s Innovation Division.
Sacyr InRoad measures the force exerted by vehicles, ground temperature, etc. 

With regard to concession assets, it is essential to know the condition of the road surface in order to maintain a level of service and anticipate future deterioration, invariably with a focus on user safety.

To that end, Sacyr Conservation and Sacyr Concessions, together with the company’s Innovation areas, are currently collaborating to implement one of these devices on the Eresma highway (A-601 between Cuéllar and Segovia).
 

In addition, Sacyr Concessions will be able to feed the Prediction Tools, which will use the data collected by InRoad to predict how road surfaces behave in the long term, based on real data. The data obtained also helps the decision-making process when building new roads.  

Cost savings and increased road safety

Regularly attending to minor road damage not only improves safety, but is up to 3x cheaper than waiting to carry out major repairs. 

Sacyr InRoad was developed in conjunction with the Instituto Tecnológico de Castilla y León to boost service quality and fulfil Sacyr’s commitment to the environment and safety for both users and workers.  

Through artificial intelligence and other innovative technologies, the use of InRoad helps prevent accidents and reduce CO₂ emissions. 

According to a report by the Spanish Roadway Association (Asociación Española de la Carretera), a well-maintained system of roads could cut CO₂ emissions from lightweight and heavy vehicles by 9% and 6%, respectively. Moreover, flat surfaces with sufficient rolling capacity reduce fuel consumption by 3%-6%. 

According to data from the Highway Safety Department of the Public Prosecutor’s Office (Fiscalía de Seguridad Vial del Ministerio Fiscal), 30% of traffic accidents occur as a result of poor road conditions.  

This project is the successful consequence of the synergies derived from the various divisions that make up Sacyr, with the ultimate goal of circulating these devices worldwide to improve road conditions on an ongoing basis.  

ISABEL RUBIO ARROYO | Tungsteno

In 2008, architect Chris Downey suddenly lost his sight following an operation. With more than 20 years' experience in his profession, he knew that he wanted to continue working in a field he was passionate about. He learned to read braille and began using an embossed printer to reproduce and interpret architectural plans. To mark the International Day of Persons with Disabilities on 3 December, we explore the story of this iconic American architect.

Downey's journey after losing his sight

In 2008, Downey was admitted to hospital for surgery to remove a brain tumour. "The surgery was successful. Two days later, my sight started to fail. On the third day, it was gone," he explained in a TED talk in 2013. At first, a cocktail of emotions gripped the San Francisco architect: "Fear, confusion, vulnerability."

But when he stopped to think, he realised he had a lot to be thankful for. "I thought about my dad, who had passed away from complications from brain surgery. He was 36. I was seven at the time. So although I had every reason to be fearful of what was ahead, and had no clue quite what was going to happen, I was alive. My son still had his dad," Downey said.

The architect lost his sight at the age of 45 after undergoing surgery for a brain tumour. Credit: TED

Sounds, textures and smells that define cities

Downey never forgot that he was "not the first person ever to lose their sight." Worldwide, an estimated 2.2 billion people live with some form of visual impairment, according to the World Health Organisation. Of these, 43 million are blind. Downey left the hospital with a mission: to get the best training as quickly as possible and rebuild his life.

And he succeeded. "As an architect, that stark juxtaposition of my sighted and unsighted experience of the same places and the same cities within such a short period of time has given me all sorts of wonderful outsights into the nature of the city itself," he explained. Subtle sounds, textures in the ground felt through the grip of his cane, the warmth of the sun on one side of his face, the wind on his neck and his sense of smell became key tools for Downey to understand space and to move and orient himself. "I started to realise that my unsighted experience was far more multi-sensory than my sighted experience ever was," he said.

Downey uses touch to design accessible spaces. Credit: CGTN America

Reading a plan by touch

It took Downey just six months to return to work. He found an embossing printer, commonly used to teach braille to visually impaired children, and opened his own architecture firm. The embossing printer enabled him to reproduce plans in a format accessible to him, allowing him to study the details of the design and form a complete picture in his mind. In order to make his own contributions and revisions to the plans, he found a solution in Wikki Sticks, pliable wax sticks that can be broken and shaped to form new lines that adhere to paper, which allowed him to add and modify lines with ease.

As Downey explains, "reading a plan through touch is very different from looking at it visually, and in some ways more difficult: you don't see the whole immediately and then understand the details; you find the detail first and then have to build out to the whole." The architect had sight for 45 years, so he says he can still visualise the space. "It's just a matter of engaging in it intellectually as I, with my fingertips, review, study and move through it," he says.

In recent years, his work has focused on enriching the environment for the visually impaired. Among his most notable projects is the LightHouse for the Blind and Visually Impaired in San Francisco, California. He has also worked as a consultant for HOK on the Duke Eye Center at Duke University Hospital and has collaborated on projects with companies such as Microsoft. He also played a key role as a consultant in the design of the Vision and Rehabilitation Hospital at the University of Pittsburgh Medical Center (UPMC).

The LightHouse for the Blind and Visually Impaired in San Francisco. Credit: Architecture for the Blind

In addition to his work as an architect, Downey serves on the California Commission on Disability Access and is a professor at the University of California at Berkeley. For him, architecture must go beyond the purely visual and embrace the tactile experience. He stresses that every detail—from the texture of walls to the design of handrails—shapes how we perceive and interact with the spaces we inhabit.

Tungsten is a journalistic laboratory that explores the essence of innovation.

Civil engineer Isabel Barba Menchen, Quality and Environment Manager at Sacyr Engineering and Infrastructure in Chile, won the 2023 Natural Innovators Award in the We Are Excellence. 

The recognition came from the innovative tool he had developed, called CALO (short for Calidad en Obra, Quality on Site), for the digital control of inspection protocols of the units of execution of the works. 

This platform optimizes communication between quality control and real-time monitorization roles. 
 

This tool was first launched in late 2023 and has been fully deployed in 2024. CALO represents a before and after for the Quality team in terms of onsite protocol control. It can be used on both mobile phones and tablets and one of its greatest advantages is that it is integrated into Sacyr's management system and can be used in any project and country.

"In construction work there are thousands of protocols that used to be carried out physically, with papers, or inspection sheets, it had to go through five signatures. CALO was created to provide service and speed up that work. We take our management systems to a digital platform that automatically reaches the devices of the people who must check the status of the work," explains Isabel Barba.

CALO has been implemented in Sotero del Rio and Buin Paine Hospitals and in the Los Vilos-La Serena and Camino de la Fruta highways. The aim is to deploy it in all projects in Chile.

Isabel has been out of Spain for 10 years, and she has been in Chile for five years. In Peru, she started the rehabilitation and improvement of the Longitudinal de la Sierra 2 Norte and then it was transferred to Cajamarca, another maintenance section. 

This engineer has also led the process through which Sacyr Chile has been certified as the first company in Chile to have a zero-waste certification and the first in Sacyr. This Aenor certification serves to validate that more than 90% of the waste in our work is recovered at the Sotero del Rio Hospital (Santiago de Chile).

ISABEL RUBIO ARROYO | Tungsteno

NASA has announced an ambitious initiative to build a revolutionary railway system on the Moon. It may sound like science fiction, but this innovative concept involves laying flexible tracks directly onto the lunar surface and using magnetic robots that levitate above the tracks to transport cargo.

The system, called Flexible Levitation on a Track (FLOAT), is designed to minimise wear and tear from abrasive lunar dust, and each levitating robot will be able to carry payloads of over 30 kilograms. The FLOAT project has already moved beyond the initial development phase. We look at the potential and challenges of this project, which NASA believes will play a critical role in supporting the establishment of a permanent lunar base by the 2030s.

Robots that levitate over a flexible track

"We want to build the first lunar railway system, which will provide reliable, autonomous and efficient payload transport on the Moon," says Ethan Schaler, a robotics engineer at NASA's Jet Propulsion Laboratory. The FLOAT project aims to develop "a durable, long-life robotic transport system” that will be “critical to the daily operations of a sustainable lunar base in the 2030s".

According to NASA, the FLOAT system would use magnetic robots that levitate over a flexible film track composed of three layers: a graphite layer that allows the robots to magnetically float over the tracks; a second layer of flexible circuitry that generates electromagnetic thrust to controllably propel the robots; and a third layer with solar panels that would generate electricity when exposed to sunlight. Unlike traditional lunar rovers with wheels, legs or tracks, "FLOAT robots have no moving parts and levitate over the track to minimise lunar dust abrasion and wear".

NASA is working to develop a robotic transport system to help astronauts on the Moon. Credit: Mirror Now

From transporting materials to exploring the Moon

The Moon is the Earth's only natural satellite. With a diameter of 3,475 kilometres, it is also the fifth largest satellite in the Solar System. There are plans to exploit resources such as regolith (lunar dust) or other minerals. A lunar railway system could transport these materials efficiently, reducing the need for multiple costly and complex missions using smaller vehicles.

NASA's goal is for each robot to be able to carry payloads of various shapes and sizes at speeds of more than 0.5 metres per second. When fully implemented, it is estimated that the system could move up to 100,000 kilograms of regolith or payload over several kilometres each day. Such a train would also allow equipment and samples to be transported safely and efficiently between research stations and to explore remote, hard-to-reach areas.

James B. Irwin, junto al vehículo lunar durante la primera actividad extravehicular del Apolo 15. Crédito: NASA.

The challenges of implementing the lunar train

The FLOAT project has entered its second phase, which will see up to $600,000 invested in a two-year study to investigate key technical and budgetary hurdles. During this phase, NASA will design, build and test small prototypes in conditions similar to those found on the Moon. It will also study the impact of factors such as temperature, radiation and lunar dust on system performance. In addition, a roadmap will be developed to optimise the manufacture of critical components such as magnetic arrays and flexible circuits.

Although the FLOAT system has the potential to transform lunar transport, it faces technical challenges. These include extreme conditions, regolith abrasion, power supply and high development costs. In addition, such a system has never been tested anywhere other than on Earth. Although prototypes can be tested under similar conditions on our planet, only an actual deployment on the lunar surface would provide the necessary data to safely validate the technology.

The FLOAT project could revolutionise lunar exploration. Credit: NASA

This project still faces numerous challenges, and NASA has not set a specific implementation date. Currently, NASA's Artemis III mission is expected to return astronauts to the lunar surface by 2026 at the earliest, marking the first manned lunar landing since the historic Apollo 17 mission in 1972. FLOAT is just one of six innovative proposals that have received funding in the second phase of NASA's Innovative Advanced Concepts (NIAC) program. Other projects include powerful telescopes, a propulsion system designed to transport cargo and people to Mars, and new power sources for future space missions.

Tungsteno es un laboratorio periodístico que explora la esencia de la innovación.

Reducing greenhouse gases is a key pillar of our Climate Change Strategy, which is why we design initiatives that prevent greenhouse gas (GHG) emissions.

As part of our strategy, we have collaborated with the Catalan Institute of Nanoscience and Nanotechnology (ICN2) and its spin-off, LightNet Carbon Capture, to utilize a material they have developed that captures atmospheric CO2.

This material, known as CO2atings®, is a coating mortar that has been tested at one of our building projects in Barcelona.

“To date, the material had only been tested in the laboratory, which is why we found it interesting to conduct a pilot test on temporary walls within a construction environment, though not part of the actual building,” explains Eugenia Riqué, Head of Quality, Environment, and Energy for Sacyr's Building Division in Catalonia.

CO2atings® was applied to four wall facings with different orientations (north, south, east, and west), and periodic samples were collected over a month to monitor performance.

“This area had higher humidity, and with the positive results from this initial series of tests, we aim to continue with further pilot tests and explore the potential for use in a unique project,” adds Eugenia.

Nature-inspired technology

This solution uses a highly efficient technology that fixates CO2 through an accelerated ex-situ mineralization process, bio-inspired by natural mineral formations such as dolomites and evaporites.

Additionally, through Sacyr Water, we have explored the potential to extract valuable materials from brine for use in producing this CO2-capturing mortar. This is currently under further analysis.

The advantages of using this mortar include the use of abundant raw materials, resistance to cracking, durability in rain and humidity, compatibility with common construction materials such as cement, concrete, and asphalt, and the fact that it does not require energy consumption.

The analysis of samples taken from the temporary facilities provided by Sacyr concluded that the material performed well on all four facades, with the highest CO2 capture observed on the north-facing facade (up to 40% by weight compared to 30% on the other orientations).

LightNet Carbon Capture, a joint venture of ICN2 and CSIC, focuses its efforts on researching materials and solutions for CO2 capture, storage, and utilization.

Black Friday is a tradition originating in the United States that has spread worldwide. Initially, the term was used to describe the traffic and pedestrian frenzy occurring the day after Thanksgiving as the holiday shopping season began.

Today, it has become a global event marked by major discounts and promotions. With the rise of e-commerce, the tradition has expanded to include Cyber Monday, the following Monday, dedicated to online deals. Both large and small businesses, whether physical or online, often extend these promotions to maximize sales.

However, as online shopping increases, so do the risks. Cybercriminals aim to exploit shoppers' haste and excitement, underscoring the importance of secure transactions and vigilance against scams.

To avoid falling victim to fraud, follow this 10-step guide to safe shopping:

1. Avoid using work devices for online shopping.
2. Don't click on links or attachments from suspicious emails. Check URLs for odd characters, misspellings, or unexpected domains when buying from international retailers.
3. Ensure websites are secure before entering personal information or completing transactions. Look for "HTTPS://" or the padlock icon in the URL. Also, review the site's privacy policy.
4. Use credit cards instead of debit cards. Credit cards offer better protection against fraudulent charges.
5. Avoid using public Wi-Fi networks for shopping. These networks make it easier for fraudsters to access your banking information.
6. Too good to be true? Be skeptical of unrealistic deals.
7. Don't use your work email or corporate passwords for external websites. This prevents recognizable patterns that could expose company credentials.
8. Keep your antivirus software up to date. Ensure your devices are protected against the latest threats.
9. Monitor your bank statements for unusual activity. If you spot unrecognized charges, contact your bank immediately to dispute them.
10. Lastly, use common sense and enjoy Black Friday responsibly!

"So called sustainable infrastructures should have cutting-edge technologies and be supported by renewable energies," explains Domingo Jiménez, Director of European Operations at Sacyr Concesiones.

In Domingo’s opinion, they should also include the principles of the circular economy and nature-based solutions. The goal is to meet our needs and improve the environment at the same time. 

"At Sacyr, we are constantly adapting to create infrastructures that meet these criteria," explains Domingo Jiménez. "25 years ago, we pioneered this in the construction of the Gran Canaria Airport, where we recycled all the demolition material of the aircraft parking platform. It was an innovative and ecological solution," Jiménez adds. He stresses: "It is not true that the most sustainable solution is more expensive than the traditional alternative."

Domingo Jiménez summarizes the keys to this vision in four points:

1)    Energy-efficient designs: They incorporate smart building designs and are energy-efficient, as they use renewable energy sources such as solar, wind, or geothermal. They will be equipped with energy management systems that optimize consumption and reduce greenhouse gas emissions. A current example of this is our Geobatt project at the Moncloa Transport Hub in Madrid. 

2)    Circular economy: A circular economy approach is needed where materials are reused and recycled to minimize waste. This also involves designing with future dismantling or demolition in mind at the end of its useful life, using sustainable materials and implementing comprehensive recycling programs. In Catalonia we have two pioneering works in the implementation of these measures: the office tower at Plaza Europa 34, in Hospitalet de Llobregat (Barcelona) and a development of 95 multi-family homes in Viladecans (Barcelona).

3)    Climate resilience: We need to develop infrastructure that is resilient to the impacts of climate change. This includes building flood defenses, using permeable materials to manage stormwater, and incorporating green spaces to mitigate the effects of urban heat concentration islands. In addition, CO2 emissions will be increasingly taken into account both during the construction and operation processes. An example could be Velindre Cancer Centre, one of the most important hospital projects in the United Kingdom, with measures such as a strict control of the carbon footprint of the materials used in construction and the incorporation of a vegetation layer used as a refuge for dormice on a nearby plot, saving transport costs to the landfill,  reducing the carbon footprint and creating a habitat for these and other animals in the environment.

4)    Smart infrastructures: Use IoT and AI to create smart infrastructures that can self-monitor, deliver real-time data, and adapt to environmental changes. Smart infrastructure will improve efficiency, safety, and sustainability. An example could be our project with Detektia, through which geotechnical behavior is anticipated to make a non-invasive monitoring of slopes and terrain thanks to InSAR satellite radar technology, rainfall and more than 30 terrain variables.

In the Elorrio-Elorrio railway project, located in the Basque Country (Spain), various innovative measures have been implemented to minimize the impact on the surrounding environment. 

Our commitment to addressing the climate emergency drives us to innovate construction procedures that better incorporate social and environmental aspects into our activities.

At Sacyr Engineering and Infrastructure, we are committed to developing environmentally friendly projects, always prioritizing sustainability in material use and construction processes. 

The Elorrio-Elorrio railway project is a clear demonstration of this approach.

Currently in its final phase, the project features several innovative measures designed to minimize its impact on the surrounding environment.

Here are six key measures that make this project particularly sustainable:

Integration of Infrastructures at an Environmental Level

As our team completes each phase of the project, hydroseeding is employed. This method uses a seed projection tank with a cannon or distribution hoses to sow seeds. 

Sowing is done on all slopes formed both by covering foundations and in the creation of embankments and clearings. The process is completed with shrub-type plantations in the final phase to ensure environmental integration.

Relocation of Excess Excavated Land

Another environmental objective achieved is the relocation of 850,000 cubic meters of surplus excavated land. This material was used to form embankments, such as in the extension of the Zumelegui Tunnel, promoting better integration with the surrounding landscape.

Restoration of the mouth of the Zumelegui Tunnel.

Environmentally Friendly Concrete

In the project, more sustainable concrete and cement was used, reducing the carbon footprint by 20-40% compared to conventional cement. These materials include 20-40% recycled content, with an emphasis on using locally sourced raw materials.

Waste Recovery

A key priority in the project’s waste management plan is the reuse and recovery of surplus materials. As a result, only 6-7% of the total waste generated has been discarded, aligning with our objective to minimize waste.

Water Use

To maximize water efficiency and prevent waste, several settling ponds have been installed near adjacent streams. These ponds act as filters before water reaches riverbeds and serve as decanters to provide water for road cleaning and dust suppression. 

During the Zumelegui Tunnel excavation, a treatment plant was installed to prevent contamination of the Goikoa stream, a tributary of the Ibaizabal River. 

Additionally, a second treatment plant was set up to handle runoff water (rainwater entering the river network), aimed at reducing suspended solids and protecting the biodiversity of nearby streams.

Arregiarte's leftover deposit.

Caring for Biodiversity

To ensure the free movement of wildlife, particularly the European mink, special crossings have been built into the drainage works along the route. These crossings include lateral steps raised above the water level, allowing animals to cross safely. Additionally, refuge areas for bats and protective sheets for amphibians have been installed at the entrances of one of the drainage works.
 

Fauna escape route.

ISABEL RUBIO ARROYO | Tungsteno

A head 18.3 metres high and a nose 6.4 metres long: these are the stratospheric measurements of George Washington's head on Mount Rushmore. Next to him are situated the heads of Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln, towering over the beauty of the Black Hills of South Dakota.

 Their dimensions would also leave some jaws agape: each of their eyes is approximately 3.4 metres wide and each mouth is about 5.5 metres across. We investigate the story behind this iconic American landmark.

Obstacles to sculpting US history

The idea to carve this iconic sculpture in the Black Hills dates back to 1923. It was suggested by South Dakotan State Historian Doane Robinson, who contacted sculptor Gutzon Borglum. The American artist decided to carve the faces of these four presidents because he felt that they represented the most important events in the history of the United States.

The project faced a number of challenges in its early days, including getting permission to carve into the mountain and acquiring sufficient funding. "For those involved, keeping the project moving forward often seemed more difficult than the actual work of carving the granite into a colossal sculpture of the four presidents," says the US National Park Service (NPS) website.

Lincoln Borglum, son of Gutzon Borglum, next to a plaster scale model of the monument. Credit: Charles D'Emery / NPS

Dynamite shaped the presidential faces

The creation of this iconic monument began on 4 October 1927 with the explosive power of dynamite, followed by meticulous carving by hand to bring the busts to life. This monumental project took 14 years to complete and involved the dedication and effort of nearly 400 workers. "The duties involved varied greatly from the call boy to drillers to the blacksmith to the housekeepers," the NPS notes.

The workers faced extreme conditions: from searing heat to bitter cold and high winds. Each day they climbed 700 steps to the top of the mountain to punch in, and then descended the wall face in a "bosun chair" supported by steel cables. The work was "exciting but dangerous," says the NPS, which notes that 90% of the rock was carved using dynamite.

Explosives were used until only three to six inches of rock remained to be removed and the final carving surface reached. At this point, drillers and assistant carvers drilled closely-packed holes into the granite in a process called "honeycombing". This weakened the rock so that it could often be removed by hand. Workers would then smooth the surface of the faces using hand tools, creating a final rock surface as smooth as a sidewalk.

Workers suspended to carve the faces of Mount Rushmore. Credit: Charles D'Emery / NPS

A hidden chamber carved into the mountain

Little did the workers know at the time that they were building a monument that would go down in history. With Borglum’s death in early 1941 and the Second World War looming on the horizon, the US Congress cut off funding for the project and all work on the memorial was halted on 31 October 1941. Over time, the sculpture has become a great icon of American history.

Today, more than two million people visit it each year, according to the NPS. Many may not know that hidden behind the giant stone heads is a chamber carved into the rock of the mountain, known as the Hall of Records, which is inaccessible to tourists.

Mount Rushmore hides a chamber carved into the mountain's stone behind Lincoln’s hairline. Credit: Business Insider

Inside the repository is a teakwood box that houses a titanium vault, covered by a granite capstone, on which the following quote from Borglum is etched: "...let us place there, carved high, as close to heaven as we can, the words of our leaders, their faces, to show posterity what manner of men they were. Then breathe a prayer that these records will endure until the wind and rain alone shall wear them away."

Tungsteno is a journalism laboratory to scan the essence of innovation.

Elena Ferrer, bioindication and bio control tech at the Northeast Tenerife Wastewater Treatment Plant.

The ecosystem created by wastewater and the microorganisms in it, is called activated sludge or mixed liquor. It consists mainly of bacteria, protozoa, metazoans, and fungi. All these beings work together dynamically, creating a true microsociety.

Bioindication encompasses all the information we can extract from the presence or absence of these microorganisms in our mixed liquor. Many of them are closely related to specific environmental variables, such as the physicochemical characteristics of the influent water (BOD, %soluble COD…), the physicochemical characteristics of our mixed liquor (temperature, %volatiles…), and operational characteristics (organic load, sludge age…).

It is a highly effective tool to understand the state of our process and the conditions of our sludge in real-time. Additionally, it helps us prevent and predict potential concerns, such as filamentous bulking or foaming.

We gather information through macroscopy and microscopy. Macroscopy is based on direct observation of both the biological reactors and our sludge in the V30 analysis; we look for the presence of foams, odors, solid loss, waxy layer formation, settling speed, clarified water turbidity, and more.

Microscopy allows to closely watch a fascinating microcosm.

With just a drop of mixed liquor, we can obtain a lot of information about the operation of our plant. Among other things, we will find out if we are conducting proper nitrification, if the organic matter in the wastewater is being removed, if we are injecting enough oxygen, if the sludge age is high, or if we have an overgrowth of filamentous bacteria. All of this is thanks to our bioindicator microorganisms.

Each treatment plant is unique and has its own identity because it is influenced by its particular characteristics, the habits of the population it caters to, and the type of process used. All these factors provide specific conditions for the development of different populations of microorganisms.

We are currently preparing a meeting between various lab techs and plant managers at Sacyr Water to share this knowledge and potentially bring bioindication techniques to many more facilities.