The　disposal　of　tailings　in　a　safe　and　environmentally　friendly　manner　has　always　been　a　challenging　issue.　The　microbially　induced　carbonate　precipitation　(MICP)　technique　is　used　to　stabilise　tailings　sands.　MICP　is　an　innovative　soil　stabilisation　technology.　However,　its　field　application　in　tailings　sands　is　limited　due　to　the　poor　adaptability　of　non-native　urease-producing　bacteria　(UPB)　in　different　natural　environments.　In　this　study,　the　ultraviolet　(UV)　mutagenesis　technology　was　used　to　improve　the　performance　of　indigenous　UPB,　sourced　from　a　hot　and　humid　area　of　China.　Mechanical　property　tests　and　microscopic　inspections　were　conducted　to　assess　the　feasibility　and　the　effectiveness　of　the　technology.　The　roles　played　by　the　UV-induced　UPB　in　the　processes　of　nucleation　and　crystal　growth　were　revealed　by　scanning　electron　microscopy　imaging.　The　impacts　of　elements　contained　in　the　tailings　sands　on　the　morphology　of　calcium　carbonate　crystals　were　studied　with　Raman　spectroscopy　and　energy-dispersive　X-ray　spectroscopy.　The　precipitation　pattern　of　calcium　carbonate　and　the　strength　enhancement　mechanism　of　bio-cemented　tailings　were　analysed　in　detail.　The　stabilisation　method　of　tailings　sands　described　in　this　paper　provides　a　new　cost-effective　approach　to　mitigating　the　environmental　issues　and　safety　risks　associated　with　the　storage　of　tailings.　©　2025　Emerald　Publishing　Limited:　All　rights　reserved.