Before the discovery of gold in the Heathcote area, the site of the Pink Cliffs Geological Reserve was open box forest with scrubby undergrowth on a layer of red-brown soil over gravel. In 1852, early prospectors discovered the first gold nuggets in the area. The significance of the site stems from it being a well-preserved example of a form of gold mining that is now redundant. Hydraulic sluicing was an important late nineteenth-century development in mining technology, which enabled the continued and more efficacious exploitation of Victoria's dwindling alluvial gold deposits. [1] [13] Information signs at the reserve highlight the mining process and its impact, noting the contributions of Thomas Hedley and John Wallace, who advanced sluicing techniques by using pumped water instead of gravity-fed systems.
Hydraulic Sluicing
In 1865, the McIvor Hydraulic Sluicing and Gold Mining Company Limited proposed to bring water from the head of the McIvor, Sandy, and Wild Duck Creeks to an elevation at Heathcote for sluicing purposes. Hydraulic sluicing is a mining method that employs high-pressure water jets to wash away soil and gravel down through a sluice box. Water for the sluicing was delivered to the site by water race, and high-pressure pipelines and hoses were then directed at the gold-bearing deposits. As the top layer of earth is washed away, any gold remains in the sluice. [12] [14] In 1874, Thomas Hedley, on behalf of the Hon. John A. Wallace, made application for water rights on the McIvor Creek and Long Gully and proceeded to bring a race belonging to the Water Trust to Heathcote. [15] Hedley was a pioneer in the development of sluicing technology in Victoria and a prominent figure in Victoria's late 19th-century gold mining industry. [1] [13]
In 1887, Hedley and Wallace began experimenting with pumping water, instead of the hydraulic sluicing method that relied on the pressure gained from the gravity-fed water race. This mining method was extremely effective, but it caused significant environmental damage and impacted local waterways and agriculture. In 1887, mud and gravel (sludge) washing back into the creek became a major concern. It was running over grazing lands, ruining the local landscape and negatively impacting the local water supply for the town, stock, and landowners. These concerns resulted in the formation of the Sludge Inquiry Board. In 1890, the gold mining operations at the Pink Cliffs Geological Reserve were closed down when the mining lease for the Heathcote Sluicing Company was not renewed, mainly due to Sludge Inquiry Board decisions. [12]
