Environmentalists are continuing to picket a New South Wales gold mine over the use of cyanide, which they claim will permanently poison the local water supply.

The Lake Cowal open pit mine, in the state's central west, began processing recently but operations were shut down yesterday and a delivery of cyanide has reportedly been delayed.

Eight protesters have been charged with trespassing but Graham Dunstan from Cyanide Watch says the protest will continue until the mine is closed.

"This mining company has been granted water leases by the NSW Government to pump up 3,650 megalitres a year for this cyanide operation," he said.

"They leave this water behind permanently poisoned. Now in a time of drought giving people the equivalent of a Dubbo's water supply each year is profligate."

The company running the mine, Barrick Gold, says it has all the environmental approvals but is not commenting today.