June 10, 2016
Photographer: Don Cherry
Summary Author: Don Cherry
Bendigo in central Victoria, Australia, has a rich gold mining history dating back to 1850. Over its first 104 years, more than 825 tons (748 tonnes) of gold were extracted from Bendigo. After a quiet period from 1954 to the late 1990s, when little mining took place, a resurgence during the last 20 years has seen more production. When first discovered the gold was relatively easily won from washing the unconsolidated sand and gravel along local streams. As mining progressed, the miners began targeting the surrounding hills for gold bearing ore. This took two forms; either in the primary quartz veins hosted within the Ordovician Period marine metasediments or in remnant ferruginated sediments which were perched on several local hill tops. Known as the White Hills Gravel, this deposit is now only found on a few hilltops as the present day streams continue to erode down through the old landscape.
Originally deposited as a quartz-rich sand and gravel in an ancient river during the late Cretaceous to Paleocene, deep weathering during the Eocene mobilized iron and silica in the water table to deposit and cement the sediments into very hard slabs. Gold that had been deposited with the gravel was then trapped within the cemented rock.
The accompanying photo shows large slabs of ferruginated river gravel which have been dug up and moved around to access the gold particles. In this location, the original surface has been lowered by as much as 6.5 ft (2 m) as the gravels were carted off for processing. After the mining, time has begun to heal the mining scars with the regrowth of local indigenous species such as the Box tree (Eucalyptus microcarpa), native cherry (Exocarpos cupressiformis) and various understory scrub species. This area is now a reserve protecting both the historic mining activities and the re-emerging native vegetation. Photo taken on May 21, 2016.
Photo Details: Camera Model: Canon EOS 600D; Lens: EF-S18-55mm f/3.5-5.6 IS II; Focal Length: 21mm; Aperture: ƒ/7.1; Exposure Time: 0.020 s (1/50); ISO equiv: 100; Exposure: Landscape Mode; Flash Fired: No (enforced).