We investigate the photodetachment of the negative ion of aluminum, initially both in the A1-(3s2 3s2p2)3p ground state and the excited 1 D state. A multiconfiguration Hartree–Fock method with nonorthogonal, term-dependent orbitals is used to generate accurate initial bound-state and final continuum-state wavefunctions. The collision of the ejected electron in the field of the residual ion is described by the B-spline R-matrix method for photon energies ranging from threshold to 12 eV. All principal scattering channels for photodetachment from both the $3p$ and $3s$ orbitals are included in the close-coupling expansion. We predict a number of prominent resonance features, whose verification presents new challenges in studies of this highly correlated process. Partial cross sections, together with the contributions of the principal scattering channels, are discussed in order to classify the resonance structure. The predicted cross sections are expected to be the most comprehensive and accurate currently available dataset for photodetachment of Al− at low energies.