What is significant?
The Thomson River Diversion Tunnel Site including the 220 metre tunnel through Stockriders Spur, the 1.2km section of river bed known as Horseshoe Bend between the tunnel's inlet and outlet, the inlet and outlet pools, and the river banks extending 20 metres either side of the Horseshoe Bend river bed.
The Thomson River Diversion Tunnel Site is located near the Gippsland gold township of Walhalla. Gold was discovered in the Thomson River valley in late 1862 and a rush to the region began. Alluvial gold mining was carried out along the Thomson River for several decades from the 1860s, although quartz reef mining became the region's predominant mining industry. The Thomson River Diversion Tunnel was constructed by the Thomson River Alluvial Gold and Tailings Recovery Company between August 1911 and about October 1912. The tunnel was blasted through a slate ridge called Stockriders Spur. The purpose of the Tunnel was to divert a portion of river flows away from a 1.2 km section of the natural river bed on either side of the tunnel known as Horseshoe Bend. The decreased flow of water around Horseshoe Bend enabled the sluicing of the gravel deposits in the river bed. From the 1850s diversion tunnels, cuttings and embankments facilitated mining along rivers and creeks in a number of Victorian goldfields in mountainous regions. Diversion mining was not common and only carried out where the natural topography was suitable. The construction of the Thomson River Diversion Tunnel was an ambitious gamble and came at a time when Walhalla's quartz mining industry was ending. The mining lease at Horseshoe Bend was declared void on 10 March 1914. Over time flooding and erosion have removed all traces of mining activity in the Horseshoe Bend river bed. The diversion tunnel is the last and longest of the thirteen river diversions tunnels surviving from the Victorian gold rush period.
The Thomson River Diversion Tunnel Site is located about 4km south-west of Walhalla in Gippsland 1.5km south of where Stringers Creek joins the Thomson River. The tunnel has been excavated under Stockriders Spur and is 220 metres in length. The Thomson River flows to the south and the tunnel extends on a downwards incline between the inlet and outlet and has a sharp change in horizontal angle prior to both inlet and outlet. The tunnel diverts a portion of river flows away from a 1.2km section of the river bed between the inlet and outlet, which is known as Horseshoe Bend. There are deep pools of water in the river near the inlet and outlet.
This site is part of the traditional land of the Gunaikurnai people.
How is it significant?
The Thomson River Diversion Tunnel Site is of historical significance to the State of Victoria. It satisfies the following criterion for inclusion in the Victorian Heritage Register:
Importance to the course, or pattern, of Victoria's cultural history.
Why is it significant?
The Thomson River Diversion Tunnel Site is significant at the State level for the following reasons:
The Thomson River Diversion Tunnel Site is historically significant as one of the last and longest of the thirteen diversion tunnels constructed for gold mining purposes in the Victoria. The tunnel was constructed between 1911 and 1912. Through its design and form the tunnel demonstrates the diversion mining technology used to divert a portion of river flows away from natural waterways and enable the digging and sluicing of river bed deposits for alluvial gold. Water diversion systems were not common in Victoria and limited to gold mining regions with a mountainous topography and perennial waterways. The looping alignment of the Thomson River at Horseshoe Bend, being an already known gold bearing locality, and the presence of Stockriders Spur are also significant as they made this location particularly suitable and were in an already known gold bearing locality. Water diversion systems are important to understanding Victoria's gold mining history. [Criterion A]
The Thomson River Diversion Tunnel Site is also significant for the following reasons, but not at the State level:
There is evidence of 1870s-80s ground sluicing in various places around Horseshoe Bend on spurs (slopes) above the river bed.
The Thomson River Diversion Tunnel Site is a place of co-existing natural and cultural heritage values. The Thomson River is listed as a Heritage River under Heritage Rivers Act 1992.