Mining operations generate large amounts of waste, which often ends up in landfills or storage sites that can cause environmental risks. Meanwhile, the construction industry is seeking more sustainable and efficient materials. Reusing mining by-products and turning them into mortar aggregates could transform waste into a valuable resource, bridging the gap between environmental responsibility and industry demands.
What Are Self-Compacting Mortars?
Self-compacting mortar (SCM) or self-compacting concrete is an advanced construction material that flows more easily, allowing it to set and compact on its own. It doesn’t need manual or mechanical vibration or compaction, which results in smoother surfaces while requiring less labor and energy on-site.
SCM can easily fill complex molds and densely reinforced areas, ensuring complete coverage while reducing the risk of forming voids and honeycombing, which can affect structural integrity. Its self-compacting property makes it easier to achieve consistent strength and density throughout the structure.
Mining By-Products: Challenges and Opportunities
Mining is essential for many global industries, but it is resource-intensive and environmentally demanding. Extracting minerals from the Earth generates massive amounts of by-products, often considered waste.
Recent studies have even found that some U.S. mines are discarding essential minerals like lithium and manganese. A year of waste contains enough lithium to power 10 million electric vehicles.
Aside from valuable minerals, other mining by-products include:
- Tailings: These are the finely ground, residual materials after mineral extraction. They usually take the form of a slurry of sediments.
- Slags: These are non-metallic by-products of smelting metal ores, which are similar in appearance to stone.
- Fly ash: This is a fine, powdery residue from burning coal in power plants.
- Waste rock: These are large, coarse rocks removed from the earth to access ores.
The responsible disposal of these by-products is also challenging and resource-intensive. Many of them contain pollutants that can harm the environment if improperly handled. As mining operations grow, so does the demand for appropriate waste management. However, this challenge also presents an opportunity.
Many mining by-products have chemical and physical properties that make them suitable as alternative raw components in construction. Some can complement or mirror aggregates essential for concrete production. Skid steers and related equipment make repurposing remnant aggregates simple. This equipment can easily transport these products with the right attachments, alongside other materials like sand or gravel for mixing SCMs. With proper engineering and processing, waste valorization in construction can turn mining by-products into valuable resources that improve construction quality while minimizing the reliance on landfills.
Engineering Self-Compacting Mortars with Mining By-Products
Researchers and engineers have increasingly turned to various alternatives for aggregates in self-compacting mortars. For example, some researchers have found a way to use ground-up seashells instead of sand in concrete production.
Some scientists and engineers have found similar uses for mining by-products. Research in mining waste recycling specifically for SCM production is still in its early stages, but materials like fly ash have found their way into the industry as potential replacements for sand and other conventional building inputs.
Ohio University professor Jason Trembly recently received an award for his efforts in sustainable engineering. One key area of his research is converting carbon waste from mining and other processes into beneficial products like engineered composites, which can be used as construction supplies.
From an engineering perspective, the key to using material alternatives is balancing proportions. Scientists can incorporate different percentages of mining by-products into traditional mixtures to see what works best. Tests for workability, density, porosity and dimensional stability can further evaluate the performance of these alternatives.
The Benefits of Mining By-Product Recovery for Self-Compacting Mortars
Incorporating mining by-products into SCM production offers multiple benefits for industries and the environment.
Waste Reduction
Recovering and reusing mining by-products for SCM production diverts significant volumes of waste from landfills and disposal sites and into productive use. This process reduces environmental hazards and removes the burden of long-term waste storage. In some regions, waste reduction can also save lives. Tailings dam failures in Indonesia in 2025 have resulted in three deaths and hundreds at risk of adverse health effects.
Lower Carbon Footprint
Manufacturing a ton of cement could generate 0.9 tons of carbon dioxide. Substituting part of the cement with mining by-products helps reduce greenhouse gas emissions and support climate initiatives. This reduction is significant for companies that aim for net zero and environmental compliance.
Resource Conservation
Replacing a portion of cement with mining by-products reduces the demand for virgin raw materials like sand and limestone. It helps preserve natural resources and reduces the need for further extraction.
Sand mining is especially harmful to the environment. It is the second-most exploited natural resource after water, with aglobal demand of 50 billion metric tons annually.
Cost Savings
Mining by-products are often available at a lower cost than traditional raw materials. Using them as SCM aggregates can help construction companies reduce material expenses without compromising performance. Reduced labor and energy needs can improve savings, making sustainable construction more affordable.
Enhanced Circularity
Mining waste recycling embodies circular economy principles by keeping resources in productive use. It encourages innovation, supports sustainable growth, and creates new economic and professional opportunities.
Paving the Way to Sustainability
Integrating mining by-products into SCM presents a promising path toward more sustainable construction materials and practices. It transforms waste into a valuable resource, minimizing environmental harm while improving the quality and cost-effectiveness of infrastructure development.
