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According to ‘ Sustainable valorisation of mine-derived solid wastes into cementitious pavement materials: Mechanical performance and microstructural insights ,’ researchers mixed blasting slag, neutralised dreg and a binder made from steel slag, waste cement and lime slag, all taken from the Zijinshan Gold-Copper Mine, then laid test roads that carried 100-ton trucks. After 28 days, the best mixture resisted deformation better than rock, soil and plain blasting slag, and it met groundwater limits for three toxic metals. The binder, called composite solid waste, combined water-quenched steel slag, waste cement and lime slag in a ratio of 17 to 2 to 1 by dry weight. An equal mix of blasting slag and neutralised dreg packed down the most densely, reaching a maximum dry density of 2.09 grams per cubic centimetre. After 28 days of service, the team measured how much each surface bent under load, where a lower figure means stronger resistance to deformation. The mixture with 15 per cent binder cut deflection by 97.19 per cent compared with a compacted blasting slag base, 63.90 per cent compared with rock, and 73.02 per cent compared with soil. The plain blasting slag base was the only one that failed the design limit, which the authors interpreted as deterioration after 28 days. In the 15 per cent road base, those metals leached at 0.007, 0.00003 and 0.02 milligrams per litre, all within the standard.
Untreated neutralised dreg released cadmium, mercury and chromium above the groundwater Class IV standard, even after long immersion. A gold and copper mine in Longyan, China, has shown that its own waste can become the road beneath its heaviest vehicles. This article explains how the mixture works, what the field tests found, and what limits remain, using a recent study. The research team, made up of Jia-Ming Wen, Xiu-Zhu Su, Yuliang Guo and Xian-Lei Fu, built the mixture entirely from material found at the mine. The safety results matter as much as the strength results.
Cost, limitations and what comes next for recycled mine waste pavement
The authors estimated material costs of 5.86 US dollars per square metre for the 9 per cent mixture and 6.99 for the 15 per cent mixture, compared with 6.92 for cement-stabilised and 6.81 for fly ash-stabilised bases. Plain blasting slag was the cheapest at 5.65, and the authors described the 9 per cent mixture as the most cost-balanced choice. That sits awkwardly beside their field finding that 15 per cent performed better, so the right choice depends on how long a road must last.