Water has been pumped from the critically full dam since late last month to protect the dam wall from collapse but heavy rain caused the spillway release lasting more than a week.
A press release was issued late on Friday by the Ministry of Health and Medical Services (MHMA) titled, “Stop using the Kwara, Tinahula and Matepono rivers now”.
“This overflow may carry with it sediments containing high levels of arsenic.”
Overnight the flow over the spillway has reportedly almost stopped.
The Solomons government declared the mine site a “disaster zone” last year over fears the tailings dam might fail, threatening about 8,000 villagers living along the river systems below.
Last month it issued mine owner Gold Ridge Community Investment Limited (GCIL) a licence to pump treated and untreated water from to safeguard the dam wall.
“All downstream communities are advised to immediately STOP using the Kwara, Tinahula and Matepono rivers until advised by MHMS and the World Health Organisation that it is safe to do so. Do NOT use river water for drinking, cooking, washing, bathing/swimming or fishing,” Friday’s Minister of Health media release said.
“In addition, downstream communities are advised NOT to eat food, including fish, from the river, NOT to prepare food or wash cooking utensils with river water, and NOT to eat animals that have died in or near the river.
“Finally, if the dam wall breaks, there may be a risk of drowning or injury due to the increased water flow. Communities should be prepared to evacuate quickly to a higher place, if required.”
The media release was issued to Solomon Islands news organisations after SBS reported on Friday the contents of a draft version dated four days earlier but that was not issued.
A downstream community leader said last week they were “panicking” about the release of untreated tailings dam water and had been “ignored by the government”.
Chair of GCIL, the landowner company that owns the mine, Walton Neazon said he had advised the downstream communities about the dewatering and to reduce their usage of river water.
GCIL said water releases by pumping and the over spillway began on March 29.
By last Friday, an estimated 150,000 cubic meters of treated and 92,000 cubic meters of untreated tailings dam water had been pumped out of the dam.
Water samples from the dam and downstream communities are due to be tested in Australia over the coming weeks.
The mine was shut down in 2014 after damage from severe flash flooding left the tailings dam critically full.
After the Solomon Islands government’s refusal to allow the then owner, Australian miner St Barbara, to dewater the tailings dam, the Gold Ridge mine and all legal liability was sold to GCIL last year for $100.