The nature and origin of brecdation and mineralization at the White Crystal ore deposit,Ardlethan tin mine,New South Wales

The White Crystal ore zone consists of an ovoid mass of fine grained quartz‐tourmaline topaz rock containing disseminated cassiterite together with prominent vughs of quartz and/or tourmaline, cassiterite, and sulphides. Toward the margins of the ore zone the decreasing intensity of alteration illustrates formation via a process of brecciation, infill, and alteration. The rectangular slab‐like fragments are commonly aligned and their plunge indicates a dip towards a common epicentre. The tourmalinized ore zone is surrounded by successive zones of sericitization and argillization. The brecciation is of large scale tensional origin which is suggestive of collapse. Beneath the ore zone mineralization/alteration continues at subeconomic grades and limited data suggests an intrusive hydrothermal style of brecciation. The entire system is a form of breccia pipe and has yielded some 1.5 Mt of ore at around 0.64% Sn.