Russian scientists have developed an innovative material for filling mined-out spaces in mines. The composite is based on man-made waste. This reduces costs, increases durability and supports the principles of a circular economy.
With the move to deep underground mining, the need for durable and cost-effective void filling materials increases to ensure safety and mine stability. Researchers propose using industrial waste instead of traditional cement to create high-strength, low-cost aggregates.
The authors of the work studied the composition and properties of composite mixtures based on coal mining waste. Crushed rock waste was used as a filler, and ash from beneficiation was used as a cement substitute. The mixtures were reinforced with additives: nanomodified silicon dioxide and glass fiber, which strengthen the structure of the material and improve mechanical characteristics.
Experiments at different stages of hardening showed that optimal combinations of components increase the strength of the material compared to compositions based only on ash. For example, a mixture with the addition of both nanomodified silicon and glass fiber shows more consistent changes in strength characteristics throughout the test.
Microstructural analysis revealed that the additives improve the formation of calcium silica hydrate (C-S-H), create a dense structure and reduce porosity, which is especially important for the durability of the aggregate under heavy load. The presence of glass fiber additionally binds the components and prevents the propagation of microcracks.
In addition to technical advantages, the proposed material meets the principles of the circular economy, since it minimizes the need for the extraction of fresh resources, recycles man-made waste and reduces the burden on the environment. The use of coal mining waste in such composites helps reduce landfill volumes and potential environmental risks.
Developing sustainable aggregate from mining waste opens up new opportunities to improve underground mining safety and reduce material costs. The introduction of such composites could be an important step towards sustainable development of the mining industry.
Source: MDPI
