Urban Mining and Precast
Although mining is filthy, destructive, and bad for the environment, it has long been the only means to obtain the metals and minerals we need on a daily basis. From cellphones to drywall, these materials are employed in a wide range of products, and as world populations rise, so does their consumption.
Source: The Hustle
Since many years ago, our continuous reliance on non-renewable resources has been a contentious topic, with business executives claiming that contemporary society simply could not run without these activities and environmentalists stressing our apparently insatiable need for damaging resource collecting. Non-renewable resources are precisely what they sound like—a wellspring that will eventually run dry.
A range of intriguing ideas has been put up to deal with the trash that already exists in an effort to recover part of the resources and embodied energy that went into creating 21st-century items. Urban mining is one of these practices; it tries to physically remove trash from landfills and recover non-renewable minerals for recycling and reuse.
The largest and most important aspect of any urban mine is the architecture and infrastructure that surrounds us. Concrete also makes up a significant portion of construction demolition materials globally since it is the most often utilized building material. Fortunately, concrete can be recycled indefinitely, making it a viable long-term substitute for mining virgin resources.
What is Urban Mining
Recovering raw materials from waste items that are dumped in landfills is a practice known as urban mining. Conceptually, it uses anthropogenic stocks rather than geological ones to satisfy industrial demands, viewing the trash produced by cities and urban environs as a useful resource.
It has been used more broadly for the recovery and monetization of any materials from any waste stream, though most people might recognize it as the recovery of metals from e-waste.
Construction Waste: Recovered materials from construction and demolition waste include wood, paper, cardboard, rubber, and metals.
Municipal Solid Waste: General recovery ranges from recycling metals and plastics to making commercial compost for sale. Also includes the recycling of metal and rubber from tires and other rubber goods.
E-waste: Electronics utilize a variety of metals that may be recycled with high rates of recovery, including some precious metals like gold, silver, and palladium.
How Does Urban Mining Work
Urban mining shortens supply chains because the resources are frequently found closer to manufacturing locations than normal quarries. As a result, less carbon emissions are produced during building.
Presorting is the first step in the complicated processing of recovered materials. Next, single- or double-stage crushing, the separation of reinforcement using magnetic separators, and occasionally sifting for separating light components follow. Sieving is the final step in the storing process.
Even with all of this, the material may still be too heterogeneous for use in buildings, in which case more advanced machinery, including sensor-based sorting systems, can be employed.
In order to create better with less and new from old, the material that was mined is recycled back into the built environment as construction material, aiding in the preservation of the world's finite resources.
While most urban mining projects utilize demolition to collect resources from abandoned structures swiftly, this method makes it impossible to separate material streams and prevents the salvaging of entire building components. Deconstruction, which is the selective dismantling and removal of materials from structures, is a more effective approach that preserves the original worth of architectural components. This adheres to the principles of the circular economy and enables construction components to be retained as near to their completed condition as feasible.
Urban Mining and Sustainability
Urban mining reuses resources and goods, reducing the need for new materials and products and related energy use and carbon emissions. This is equivalent to using one product rather than two. This lessens needless manufacturing and promotes the effective use of already-available resources, helping projects cut costs and save time.
Therefore, widely adopting urban mining may significantly lower production cycle emissions and unconstrained resource use.
Stone and sand must be mined before they can be used to make concrete for a structure. They are joined together by cement, which is formed of clay, silica, limestone, and other natural materials. Steel, which takes energy and produces CO2, is used to support concrete. Iron ore mining also contributes to air and water pollution. Then, these materials are used to make more sophisticated components.
Each stage requires time, energy, effort, emissions, and labor expenses associated with production, transportation, and labor costs, all of which have an effect on the environment. In light of this, every production stage—from extraction through manufacture and assembly—increases the cost of a building product. When we take the time to deconstruct structures and repurpose things for their original (or an even greater purpose), this extra value accumulates in a product that is now in a building that is made from recycled materials.
Why Urban Mining Is Not More Common
The built environment is not currently being constructed or maintained using secondary materials by the construction industry. Logistics, the desire for recycled resources, and performance perceptions are the obstacles to expanding urban mining. The biggest obstacle to overcome is the lack of knowledge about the resources that may be harvested and their potential worth for reuse.
The frontline players (developers, architects, contractors, and governments) in cities worldwide can be mobilized to grab the circular opportunities in the urban mining once the insights and benefits of this practice are made more widely available.
Key Takeaway
For us to function within more sustainable bounds, our supply chains must be more robust, and our waste-intensive behaviors must be reduced. Particularly, the built environment needs to be made to be far more sustainable.
For cities and regions, the initial stage is to merely map out all the important resources that are present there. All we have to do is start digging to find the urban mine that can support our future construction efforts.