History
The Coffs Harbour Eastern Breakwater extends into the sea in a north-easterly curve from the end of Corambirra Point (or South Coffs Headland). The eastern breakwater at Coffs Harbour was built as a part of a larger program of harbour works that also saw the formation of the northern breakwater than connects Muttonbird Island to the mainland and filling in of the viaduct (trestle bridge) and part of the harbour to link South Coff Island to the mainland. The works were designed by government engineers de Burg and Keele in 1910-1911 to create a safe and tranquil shipping harbour following the completion of the government jetty in August 1892 and the rapid growth of the timber, sugar cane, and dairy industries around Coffs Harbour. The two breakwaters link North Coff (Muttonbird) and South Coff Islands to the mainland and enclose some 200 acres of water (at low tide). The eastern breakwater was originally 1200 feet long and curved towards Muttonbird Island to form a man-made harbour entrance.
The first stage of works that began in 1913 was to build a viaduct or timber trestle bridge that linked South Coff Island to the mainland. This was done so that the base of South Coff Island could be used as a quarry to source rocks for the breakwaters. By 1915 a rail line had been built to transport the rocks from the quarry to where the northern breakwater was to start.
Geology
Construction aggregate, or simply "aggregate", is a broad category of coarse particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates. Aggregates are the most mined materials in the world. Aggregates are a component of composite materials such as concrete and asphalt concrete; the aggregate serves as reinforcement to add strength to the overall composite material. Due to the relatively high hydraulic conductivity value as compared to most soils, aggregates are widely used in drainage applications such as foundation and French drains, septic drain fields, retaining wall drains, and road side edge drains. Aggregates are also used as base material under foundations, roads, and railroads. In other words, aggregates are used as a stable foundation or road/rail base with predictable, uniform properties (e.g. to help prevent differential settling under the road or building), or as a low-cost extender that binds with more expensive cement or asphalt to form concrete.
To claim the find, you need to answer the following questions:-
1. What are the three main colours that the rocks are coloured?
2. Which way does the quartz grain run through primarily (Vertical or Horizontal)?
3. In addition to answering the questions, you can optionally take a photo of yourself and your GPSr and post it with your log.
Please log as found and email the answers to brad1987, if there's anything wrong, I’ll be in touch.