PENRICE, in 1939, ICI (Aust.) Ltd commenced quarrying operations to supply calcium carbonate for soda ash production. Initial operations were on several quarries on sections 333, 334, and 167, before shifting the main plant to the Penrice quarry in 1950. In 1989, the soda ash plant, along with the Penrice quarry and solar evaporation saltfield at Dry Creek, were sold to Penrice Soda Products Pty Ltd. The Penrice marble deposit is part of the Early Cambrian Angaston Marble of the Normanville Group, originally deposited as lensoid limestone reefs which were subsequently metamorphosed, recrystallised and folded. The deposit is 180-280m thick, on the near-vertical eastern limb of a S-plunging, partly overturned anticline. The high-grade central part of the marble formation is generally 95-98% CaCO3, and is flanked by lower grade zones (<95% CaCO3) which are darker in colour due to contaminants, and interbedded calc-silicates. The large open cut follows the marble bed in a NNE direction. Higher grade material is railed to the Osborne plant for soda ash & sodium bicarbonate production, with a proportion used in Adelaide Brighton Cement Ltd Angaston cement works. Construction material is generated from byproducts of soda ash plant feed. The balance of production is for construction materials, whiting and agricultural lime. Adelaide Brighton Cement Ltd retains reserves in other marble deposits in the same formation elsewhere in the region. Total production for the period 1939-2013 is in the order of 50Mt, of which ~32Mt was for an industrial use, and 18Mt was for construction materials. Recent annual production is in the order of <1Mtpa, and of construction materials only. Annual production of soda ash was in the order of 400,000t. For the majority of mine life there were no total resource figures published. May 2012 resource statement was 28Mt chemical grade limestone, 39Mt construction material grade. Calc-silicate for higher quality construction material products also available with quarry expansion. There was production of chemical grade limestone for lime manufacture (but not for soda ash, see below), and production of material for the construction industry. As of June 30, 2013 Penrice Soda Holdings closed the Osborne Adelaide soda ash plant, switching from manufacture of soda ash to importing and distribution through the JV partner Pro Asia Pacific Pty Ltd sourcing soda ash from American Natural Soda Ash Corporation (ANSAC), the world's largest soda ash exporter. The soda ash plant was decommissioned, and the sodium bicarbonate plant modified to accept imported soda ash. A new lime plant is fully operational. In 2014 Penrice sold the quarry to Adelaide Brighton, who continues to operate the quarry to supply material to its lime and cement plant in Angaston. Angastonite, a rare hydrated phosphate with the formula CaMgAl2(PO4)2(OH)4.7H2O was discovered in 1989, and identified in 2010 (see MESAJ 58)