Invierno is a surface mine that uses a typical truck and shovel mining method. The mine has recently introduced blasting to remove the overburden which is also being carried out by hydraulic excavators. Invierno utilises 240 tonne capacity trucks for overburden and 100 tonne capacity trucks for transport of coal to the port's stockpile. The strip ratio at the mine is relatively low with plans designed to keep overburden removal volumes stable during the life of the operation. Most of Chile's coal fired generating units are built for burning bituminous coals; therefore Invierno's sub bituminous coal product penetration into the domestic market is a slow process as plants blend and test it in boilers.