tps.org.au

H.C. Webster photo of "Brisseis Tin Mines " showing the Southern end.

Cheers Kerry Spurling postcard of hydraulic tin Sluicing N.E. Tasmania. Any ideas as to where this is.

Cheers Kerry

By Jeff Harris. I have just noticed these two postcards. Both of them show views of the Briseis tin mine which was located within the township of Derby. The lower postcard was published by Spurling & Son, Launceston and printed in Prussia (No. 207). The Briseis mine was owned by the Krushka Brothers who came from nearby Moorina, which was originally known as Krushka's Bridge. At first the mine was known as the Brothers Mine, but was eventually renamed the Briseis Tin Mine. Briseis was a 3y.o. filly that won the !876 Melbourne Cup. The Briseis Mine was very successful, producing up to 120 tons of tin per month. It was a very large mine, requiring large volumes of water for the sluicing process. The Ringarooma River (which separated the mine from the main street of Derby) was the main source of water but was unreliable in the summer months. Consequently (in 1924) a dam was constructed across the Cascade River some 5kms. upstream from Derby. This river joined the Ringarooma at the southern end of the town. The dam was very large. It was 70 feet high, the length of its crest was 430 feet, the base was 160 feet from the front to the back and it had a capacity of 750 million gallons.

On the 4th. of April 1929, the dam wall partially collapsed after 14 inches of rain was recorded upstream in 24 hours. Initially, about 4 feet of water was observed flowing over the spillway which was at the side, but the spillway was unable to cope and eventually 3 feet of water began flowing over the entire top of the wall. The dam broke, sending a wall of water (that was estimated to be between 80 and 100 feet high) surging towards the town and the mine. There were 14 fatalities recorded in Derby. Parts of the town and the mine were badly damaged by the floodwaters. The force of the water caused the Ringarooma River to flow backwards towards Branxholm. The mine reopened after five years with reduced output. However, the price of tin fell dramatically after WWII concluded and the mine became unviable. It was eventually closed in 1948.