Impact of machine traffic events on the physical quality of a minesoil after topographic reconstruction

Abstract Excessive traffic from large machines during topographic reconstruction promotes the persistent topsoil compaction in the minesoil around the world. Therefore, this study aimed to measure the impactof machine traffic events on the physical quality of a minesoil immediately after topographic reconstruction.The study was conducted in a minesoil recently constructed, on which 0.70 m of clay topsoil was placed. During topographic reconstruction, different traffic events (zero, one, three, five, eight, and twelve passes) over a 12-meter transection were simulated, totaling six treatments. Before and after traffic events soil samples were collected from the 0.00 to 0.10 and 0.10 to 0.20 m layers to evaluate bulk density, soil porosity, distribution of water-stable aggregates, preconsolidation pressure, degree of compactness, soil water retention curve, and soil penetration resistance. The minesoil restoration using topsoil with 473 g kg−1clay and 216.31 g kg−1 of soil moisture proved highly susceptible to compaction when subjected to the first machine traffic event. Bulk density, soil porosity, soil pre-consolidation pressure, and degree of compaction were highly sensitive to respond to the first machine traffic event, while the macroaggregation formed by compression machine and an increase of soil water retention was observed after twelve tractor passes. Before the topographic reconstruction operations of the minesoil, the topsoil must be subjected to a Proctor test to establish a soil moisture level to minimize the impacts of machine traffic.