A TROUBLESOME mine shaft known as Little 180 Mine near the Marong and Eaglehawk roads intersection in Ironbark has reopened after heavy rain, the City of Greater Bendigo says.Bendigo Historical Society president Jim Evans said the Little 180 Mine dated back to the 1890s and extended to a depth of more than 1300 feet into Sheepshead Reef. The council’s presentation and works manager Alex Malone said the sinkhole was discovered on Friday.“It was while mowing the area that a council worker noticed the ground looked sunken and uneasy,” Mr Malone said. The area was fenced off on Friday, but Mr Malone said the fencing had collapsed into the old mine by Saturday.“We are now capping the old mine by digging down far enough to create a solid platform before we build a foundation from concrete,” he said. “This will ensure the area is safe and the mine is secure.”Mr Malone said there had been about 30 sinkholes reported to the council in the past 12 months.