Emptying Queensland’s flooded mines

The term unprecedented has been a popular descriptor for the devastation that Queensland has experienced over the past few weeks.

Three quarters of the state is flood-affected, many thousands of lives and livelihoods disrupted, and a good many of its mines filled with rain and a healthy dose of topsoil.

According to the Queensland Resources Council only 15 per cent of all Queensland coal mines are fully operational, with a full 85 per cent either operating with restrictions or yet to resume operations. At least one mine will be out of operation until mid-February.

While the extent and magnitude of the floods may, or may not, have precedents there is much to be learnt from past wet seasons where La Nina has been a visitor to our shores.

In January and February of 2008 heavy rains in Central Queensland resulted in flooding of coal mines in the Bowen Basin and the submergence of a drag line. In the weeks and months that followed the then Queensland Environmental Protection Agency granted special discharge conditions (what is known as a Transitionary Environmental Program; TEP) to impacted mines as they were forced to discharge floodwaters into the Fitzroy River catchment.

In response to the recent flooding the now Department of Environment and Resource Management has already issued TEPs that allow variations to water management conditions for 12 mines.

The 2008 wet season proved that emptying flooded mines can present as big a challenge as having them filled. The longer flood waters remain in the mine pit the more time they have to collect natural salts. Moreover as rivers subside they become more sensitive to the discharge as the discharge represents a greater proportion of the river’s volume.

In 2008, a total of 138 GL of mine-affected water was discharged to the Nogoa-Mackenzie-Fitzroy River system from a single flooded mine over a period of seven months.

This, combined with the impacts of discharges from other mines reduced the spawning success of at least one fish species and the suitability of river water for downstream consumption, but the long term impacts on river ecology are largely unknown.

The intensity of the cumulative impacts of discharges from multiple mines stretched a system that is traditionally geared toward the regulation and management of individual mines. Following these events the Queensland Government appointed Emeritus Professor Barry Hart to investigate and in response the Queensland Department of Environment and Resource Management standardised and tightened discharge conditions, undertook cumulative impact modelling and helped establish The Fitzroy Partnership for River Health, a multi-stakeholder body with a mandate to assist the coordination and management of water quality in the basin.

The greater extent of flooding this wet season will test these reforms, but they do represent an attempt to address cumulative impacts through catchment wide management. 

In the Hunter Valley of New South Wales mine water discharge is regulated by the Hunter River Salinity Trading Scheme. The Scheme was first trialled in 1994, and implemented in 2003. Under the trading scheme, salty water can only be discharged when the salt concentration in the river is low. Under low river flow conditions, no discharges are permitted; under high flow conditions limited discharges are allowed as determined by a system of tradable salt credits.

Under flood conditions, unlimited discharge is permitted (up to a threshold salt level). Mines and electricity generators hold a license for a certain number of credits which permits them to discharge salt into a river block in proportion to the number of credits they hold (one credit allows the holder to contribute 0.1 per cent of the total allowable discharge).

There are a total of 1000 credits in the trading scheme; these may be traded among stakeholders in the marketplace. The New South Wales Department of Environment, Climate Change and Water has reported that since the introduction of the scheme the target salinity level of 900 EC has not been exceeded as a result of discharges.

The Hunter River Salinity Trading Scheme, as well as the reforms in Queensland are part of a bigger push to better manage cumulative impacts in the resources sector. The Queensland Department of Infrastructure and Planning has recently placed conditions on a number of new resource projects that require proponents to undertake regional monitoring and management in collaboration with other companies; coordinate industry social infrastructure investments; and establish multi-company community consultative committees.

These initiatives are seeking to encourage greater collaboration and coordination between industry and government and overcome the limitations of mine by mine management approaches. Whether such collaborative reforms will be well enough established to handle an event as significant as Queensland’s recent flooding is a question of an altogether different kind that will require the serious attention of policy makers and companies in the coming months.


Dr Daniel Franks is a Senior Research Fellow at the Centre for Social Responsibility in Mining, Sustainable Minerals Institute, University of Queensland.


This article was first published by ABC the drum – http://www.abc.net.au/unleashed and has been reprinted with their permission.



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