Quarrying of the basalt plug at Prospect Hill was well underway by the mid-nineteenth century. By the early twentieth century, Prospect Hill land had been acquired by quarrying firms anxious to expand their land holdings near this valuable source of raw material. The bulk of the present CSIRO site was acquired by the Commonwealth in 1946, and a further 15 hectares was acquired in 1963. In the early 1950s the site became operational and sheep were pastured for research purposes. Prospect Hill was for many years the primary source of road-stone for the city's expanding infrastructure until the reserves of dolerite were exhausted. The Greystanes estate was eventually bought by quarrying interests.