Guildford said the offer was open for acceptance up until 5pm on July 23.
“The board is considering and evaluating this offer and will update shareholders in due course,” the company said on Thursday.
As part of the deal, Singaporean company offered to acquire the assets through a non‐interest bearing convertible promissory note.
Guildford said this matures six months after issue and was payable in cash or may be converted into shares of the purchasing company.
Any deal will be subject to shareholder and stock exchange approvals and other conditions.
Guildford has stakes in eight coal projects in Queensland, across the Galilee, Bowen, Surat, Maryborough and Mulgildie basins.
Yet its cash flow will come from the completed Baruun Noyon Uul mine in Mongolia which produces 1 million tonnes per annum of low ash, low sulphur hard coking coal.
Earlier this month the Mongolian government granted Guildford a coal haulage permit to export its coal from the BNU mine to China.