The mineshaft, located on the corner of Grant and Walker Street near ruined buildings of a former mining operation, dropped on Saturday and was attended to by  City of Ballarat emergency services.

General manager Terry Demeo said emergency council staff discovered the cap on Central Plateau Mine No 2. Shaft. 

“The timber cap was placed on the mine over 100 years ago and deteriorated over time This mine finished operating in 1915 due to rising water and a diminishing payload,” he said.

“It is at least 254 metres deep with a horizontal drive recorded at that depth but newspaper reports from the era mention gold being recovered at a depth of 670 metres.”

The Victorian Historical Mineshaft Chasers group member Dean Anthony said some documents suggested the mineshaft had originally been called the Band of Hope and was one of the wealthiest gold mines in the world. 

However investigators at the historical society said later documentation said it belonged to Central Plateau Mining and had a low gold yield.

Historical Society's Michael Cuttle said if the mine was the Central Plateau, it was one of the last mines to be closed in the Ballarat area. At the stage of its closure it had not recorded high yields of gold, he said.

“It was the last mine to work in the Sebastopol area. The last one in Ballarat itself closed in 1910.”

Mr Cuttle said most of the mines in Ballarat closed when men went to war, simply because there were not enough men to work in them.

DELWP has agreed that council will undertake the rectification works and DELWP will meet the costs. 

Council will excavate around the mine opening and install a purpose-built steel lid, reinforced by concrete and capped with compacted soil. 

Work will start as soon as the weather conditions improve.

“As a historic mining city, there are numerous shafts around the municipality, and most of them are mapped,” Mr Demeo said.