Dunes derived from Yamba Formation gypsiferous beds are mantled with flour gypsum in the Yamba-Noora area. They have been a source of agricultural gypsum for Riverland irrigation areas since the early 1900s. Auger drilling located 6 deposits with good potential and another 6 that warrant further investigation. The good deposits are large, have an average thickness of 0.5 metres of flour gypsum and a gypsum content between 80 and 95%. In the underlying fine seed gypsum, the grade generally declines markedly, with sand as the main contaminant. Salt (NaCl) is the only deleterious impurity. Recorded production, since 1916, totals 17 790 tonnes but large tonnages have been mined from deposits without mineral tenure. Reserves are extensive and are sufficient for many decades.