Unusual post-mining sulfates from the Peelwood and Lloyd mines, New South Wales, and a comment on wattevilleite

Alpersite, monoclinic MgSO4·7H2O, and chalcanthite, CuSO4·5H2O, have been identified in efforescences on a tailings dump at the Lloyd copper mine, Burraga, New South Wales, in the same setting as that associated with an earlier reported occurrence of boothite, monoclinic CuSO4·7H2O. Analyses of alpersite gave the compositions (Mg0.628Cu0.294Zn0.059Mn0.019)SO4·7H2O and (Mg0.450Cu0.325Zn0.160Mn0.062Co0.003)SO4·7H2O; chalcanthite was of essentially stoichiometric composition. Powder X-ray analyses of a sample of a white, chrystalline efforescence lining a retention pond receiving run-off water at the Peelwood mine, Peelwood, New South Wales, showed it to consist of a member of the epsomite group, together with subsidiary amounts of the poorly characterized species wattevilleite, Na2Ca(SO4)2·4H2O(?). Dehydration of the material at 0°C gave a single phase that was identified as a member of the hexahydrite group and analyses showed it to be bianchite of composition (Zn0.582Mg0.380Mn0.037Cu0.001)SO4·6H2O. Its precursor was thus goslarite with the same cation distribution. A re-examination of the data in the ICDD powder diffraction file for wattevilleite shows that the diffraction pattern reported is that of hexahydrite, MgSO4·6H2O. Reported analytical data for wattevilleite, together with results of studies concerning phase relationships for alkali and alkaline earth supfates, indicate that it is probably a mixture of other species.