The main reason Bunbury is here at all is because of the lava flows 137 million years ago that created the Bunbury Basalt. In outcrops from Bunbury to Black Rock east of Augusta, it has been a major geological feature that has shaped our coastline for millennia.1.
Basalt = lit. ‘very hard rock’
At Gelorup, Indigenous people used the basalt for toolmaking for thousand of years, striking it against the quartz rock from Boyanup (= ‘place of stone’). Europeans began quarrying the basalt at the back beach in Bunbury, but later moved quarrying to Gelorup, where as early as 2002 the WAPC recognised “It is of particular significance to the State and the South-West Region as it is a near surface deposit with high and consistent quality, and has good accessibility to the Greater Bunbury and South-West markets. The resource has a quarrying life of 30 to 50 years… It is considered to be in the States interest to maintain mining access to the resource.”2.
The near surface rock was acknowledged by the WA Dept of Mines as being “of strategic importance for the entire Bunbury Region… used … for general building and construction as well as precise specification, (unusually) high strength concrete aggregate, hard stand construction, road formation construction and has unusually favourable properties for top dressing bitumen roads…”3.
The Dept of Mines continued to state that “… the high specification of the rock results in it being transported as far as Perth and Albany for certain projects” and critically, “No other alternative sites for other rock with similar specifications have been reported in the region.” “The Gelorup locality has the lowest production costs of all of the possible alternative sites for Bunbury Basalt, in a large part due to the proximity to the market. As for all basic raw materials, the cost of transport is a significant component of the overall cost. The wider community benefits from having a suitable relatively low cost, long term supply of aggregate from the Gelorup locality. For example, savings from lower construction costs of infrastructure such as roads and public buildings can result in more public funds for other community projects and services.”4.
These are strong economic and future thinking arguments for retaining access to this strategic resource.5. So you can imagine my dismay and frustration when Main Roads WA proposes to use $852 million of State and Federal Govt money (our money!) to ‘sterilize’ ie waste over 13.6 million tonnes, or $683 million worth of basalt!
Continued in the next Post – ‘”… and where it could all end.”
REFERENCES / CREDITS
- Vivian, Geoff, (2016) Supercontinent rift formed bizarre Bunbury rocks, retrieved from https://phys.org/news/2016-05-supercontinent-rift-bizarre-bunbury.html. Image by Glenn Crouch, Aegir Photography.
- Western Australian Planning Commission (2002) Gelorup Basalt Quarry Buffer Study.
- Capel Shire Council Minutes – 13 Feb 2002, p 51. (Submission from the Dept of Mines and Petroleum) on a Quarry Licence Extension Application
- For more information, check the supporting documentation for Capel Shire Council Resolution (OCM 219/2019), and from Item 14.2 of the Capel Shire Council Ordinary Council Meeting of 16 Dec 2020.