The main raw material for lime production is shellsand sourced from the ocean floor. Shellsand is dredged from the seabed at Owen Anchorage and landed at Woodman Point (pictured below) where it is washed to remove salt and silt. The washed shellsand is then pumped as a slurry to a stockpile at the Munster Plant.
Cockburn Cement has been dredging shellsand from Owen Anchorage since 1972 under the terms defined in the Cement Works (Cockburn Cement Limited) Agreement Act (1971). Cockburn Cement currently dredges under an approval dated 2009 in which the WA Environmental Protection Authority granted permission for Cockburn Cement to dredge shellsand from areas of West Success Bank for a maximum of 20 years. These dredging areas are free of seagrass, as Cockburn Cement is not permitted to dredge areas with seagrass under its current approvals. As dredging on West Success Bank commenced in July 2010, these approvals remain valid until July 2030.
Cockburn Cement dredging in Owen Anchorage has also previously
been used by the State Government to help develop a second shipping
channel into Cockburn Sound and to widen the existing shipping
channel. Since 1994 Cockburn Cement has spent over $8
million on rehabilitation of seagrass and research into the
environmental impacts of dredging operations.
These operations are the subject of the Environmental Management Programme (EMP) detailed in this section.