зах зээл дээр хамгийн жижигхэн чулуулаг бутлуур
нураах бутлуур. English for Mining Engineers: March 2012. There are no definite line of division between maintenance and repair. It is usual to say that maintenance includes items such as cleaning, inspection, adjustment, routine replacements, and hard face or other build – up welding, while repair consists of fixing or replacing worn or broken parts.