This　paper　investigates　a　new　resource-allocation　problem　involving　multi-resource　operations,　where　completing　an　operation　requires　simultaneous　use　of　multiple　(renewable)　resources,　probably　of　different　types.　The　goal　of　the　study　is　to　provide　a　solution　method　that　minimizes　the　makespan.　The　authors　formulate　the　problem　into　a　novel　mixed-integer　linear　program　(MILP)　model.　To　efficiently　solve　practical-sized　instances,　an　exact　Benders　decomposition　algorithm　is　developed.　This　algorithm　divides　the　original　problem　into　a　master　problem　of　allocating　resources　and　a　subproblem　of　calculating　the　makespan,　and　both　are　linked　via　Benders　cuts.　The　convergence　is　sped　up　by　improving　the　mathematical　model　and　embedding　the　variable　neighborhood　search　algorithm.　Compared　with　CPLEX,　a　commonly　used　MILP　solver,　the　computational　results　demonstrate　that　the　proposed　algorithm　provides　tighter　upper　and　lower　bounds　in　most　instances.　In　particular,　compared　with　CPLEX,　the　proposed　method　can　on　average　improve　the　upper　and　lower　bounds　by　4.76%　and　4.39%,　respectively,　in　solving　practical-sized　instances.