SINGAPORE, Nov 9 (Reuters) - South Korea's GS Caltex has started December-loading spot gasoil discussions via a sales tender that closes on Friday, with volumes nearly similar to those loading in November, three sources close to the matter said on Thursday.

The private refiner is offering at least four cargoes of gasoil with a sulphur content of 10 parts per million (ppm), one cargo of 50ppm sulphur gasoil and three cargoes of 500ppm sulphur gasoil.

All of these cargoes are around 300,000 barrels in size.

The 10ppm sulphur gasoil cargoes are scheduled to load Dec. 14-16, Dec. 20-22, Dec. 25-27, Dec. 27-29, while the 50ppm sulphur gasoil cargo is to load Dec. 8-12.

The 500 ppm sulphur gasoil cargoes are supposed to load Dec. 3-5, Dec. 5-7, Dec. 12-14.

The refiner sold at least seven gasoil cargoes loading in November, of which four were 10 ppm sulphur gasoil.

GS Caltex typically does not comment on commercial matters. (Reporting by Trixie Yap; Editing by Christian Schmollinger)