Among its conclusions was that ‘‘because of the significant environmental, social and cultural values of Tuggerah Lake and the potential for mining subsidence to impact on these values, no mining causing subsidence of the Lake should be approved unless a high level of knowledge about the Lake’s ecology and hydrology (including seagrasses, tidal flows, currents, water quality and mixing) has been demonstrated and sufficient certainty and assurance provided to ensure that there would be no unacceptable adverse impacts on the Lake or its key values’’.

But when it comes to Lake Macquarie in the year 2012, it appears such social and environmental worries may carry somewhat less weight.

Centennial Coal has been given approval by the department of planning to mine beneath about 15 square kilometres of Australia’s largest saltwater coastal lake. This represents about 13 per cent of the lake that will be exposed to the risk of subsidence, predicted to be ‘‘up to 65 centimetres’’.

In approving the mining plan, the department has overridden objections from the Hunter-Central Rivers Catchment Management Authority, which has warned of ‘‘uncertainty regarding potential adverse effects over a significant portion of the bed of Lake Macquarie’’.

According to the department, Centennial has committed to assessing the possible impacts before ‘‘secondary extraction’’ of coal – such as pillar removal – occurs. It is hard to say whether this will comfort the doubters.

Lake Macquarie residents haven’t yet forgotten what happened to the Chain Valley Bay shore when state-owned mines removed pillars under the lake. Low-lying areas of land were drowned as the mines subsided.

Some may find it disturbing that the planning department – which recently backed mining near Glennies Creek against the advice of the NSW office of water – appears quite ready to dismiss warnings about the possible effects of mining on lakes and river systems.