What is significant?
The Thomson River Diversion Tunnel is located about 4km south-west of Walhalla in Gippsland, 1.5km below where Stringers Creek joins the Thomson River. The tunnel was driven through a ridge of land called Stockriders Spur, around which the river formed a horseshoe bend.
Diversion tunnels facilitated alluvial gold mining along the former courses of rivers. After completion the river would flow through the tunnel, allowing in summer time most or all of the flow to be diverted so that the river bed could be sluiced for alluvial gold. In winter the volume of water flow would probably resume the former course, making sluicing very difficult.
Construction of the Thomson River Diversion Tunnel by the Thomson River Alluvial Gold and Tailings Recovery Company was begun in August 1911. Work started at the outlet end and the tunnel was driven at an incline through the slate rock. Construction was completed around October 1912 by blasting through rock at the inlet end. The total length of the tunnel is about 561’ (171m). The tunnel is not straight, but reportedly has a sharp change of angle below the entrance and again near the outlet. The entry and exits of the tunnel contribute to the significance as the most visible evidence of the scope of the undertaking.
The fortunes of the Thomson River Alluvial Gold and Tailings Recovery Company are not known, but the working of the horseshoe bend of the Thomson River is not believed to have brought significant dividends. Alluvial mining was never a major feature of the Walhalla field, being confined to sluicing on the beds and banks of Thomson River and its tributaries. In 1886, the mining surveyor observed that nearly all the beds had at some time or other been passed through the sluice-box.
How is it significant?
The Thomson River Diversion Tunnel is of historical and Archaeological significance to the State of Victoria.
Why is it significant?
The Thomson River Diversion Tunnel is historically and archaeologically significant as evidence of one of the dying stages of an industry that had dominated Gippsland for over fifty years. The settlement of the Walhalla area from the mid 1860s had been on the basis of reef mining. With the rapid decline in the fortunes and subsequent closure in 1914 of such prolific mines as Long Tunnel, the sluicing of this part of the Thomson River was one of the last initiatives to win payable gold. Sluicing for alluvial gold in the Thomson River in 1912 had turned the Walhalla wheel full circle from the first prospectors working for gold in Stringers Creek in the early 1860s. The tunnel is significant as one of the last and longest diversion tunnels constructed for winning gold in the Victoria.
The Thomson River Diversion Tunnel is socially significant as a component of one Victoria’s most evocative gold mining landscapes. The tunnel contributes to a unique cultural and historical landscape, which was dominated by gold in the nineteenth century, but a landscape with little permanent evidence of its former importance.
THOMSON RIVER TAIL RACE/DIVERSION TUNNEL - History
Heritage Inventory History of Site: According to Aitken and Supple et al, the tunnel was cut through a hill to divert the Thomson River and enable alluvial miners to work the dry bed of the river. This interpretation varies from the mining surveyor's account of the tunnel's purpose in 1871: 'At Cooper's Creek a party are engaged in tunnelling in the bed-rock, to form a tail-race for the purpose of draining the flat, which is supposed to be the old bed of the Thomson River.'References: Aitken, p. 39 Mining Surveyors' Reports (Stringer's Creek Division), December 1871 Supple et al, Site M24 (i)