Washington authorities claim no higher radiation levels have been detected at the site, but the leak could be in the range of 150 gallons to 300 gallons.
The country rejected Saturday an independent report claiming security forces used white phosphorus in a crackdown on a Chinese-backed copper mine protest last November.
To date, Vista had invested over $9 million in the water treatment programme and the construction of the automated management system, at the Mt Todd mine site in Northern Territory, Australia.
World's biggest diamond producer said Friday jewellery demand will experience moderate growth this year, which represents a major shift from the 12% decline in rough diamond prices last year.