Threats to water supply halt mining projects

The government has put upcoming coal projects on hold following an independent report warning of the damage posed to Sydney’s drinking water by local mining operations.

GlobalData mining writer Scarlett Evans has investigated the impact of mining projects on water supplies.

“Fears over water supply in Sydney, and indeed the whole state of NSW, have been growing in recent years,” Evans said.

“Dam levels are dropping at the fastest rate since 1940 and figures from WaterNSW show that the warning storage level was reached in January this year, with Sydney’s desalination plant stepping in to provide drinking water to residents.

“As of November, dam levels were found to be at less than half of capacity (47%), and some mines in the state have warned they may soon run out of water entirely,” Evans continued.

Evans explained that a report authored by a panel set up in 2018 — tasked with investigating water losses in Sydney’s drinking water catchment due to mining operations — found that mining could cause water losses of up to as much as eight million litres per day (equivalent to 2920 million litres per year).

She detailed that the primary cause of water losses is longwall mining, a method that can lead to subsidence or the collapsing of land. This process blocks the flow of water, which continues to be a problem after the mining sites have been shut down.

Nic Clyde, from environmental organisation Lock The Gate, said, “A lot of water continues to flow into the mines that have been shut down, because there are voids left where coal has been removed. That water flushes out heavy metals, salts — all the things you don’t want in your freshwater supplies.

“In some cases there’s no real way of stopping it. Once you’ve mined the coal, you’ve got a problem — and I’m not sure if anyone really knows how long it will last.

“We’ve got a climate that is getting hotter and drier, a growing population, and we’re in the grip of one of the worst droughts in living memory. The question is — how much is too much?

“The mining industry might like to play down the damage to the catchment, but there are some very big questions and expensive problems that need to be solved.”

While the government’s pause is welcome, industry members remain uncertain as to what the outcome will be.

Image credit: ©stock.adobe.com/au/martinlisner