MA: Representing Coal An (Mei An)

Supervisor and issuing unit: National Safety Mark for Mining Products;

Place of use: underground coal mine

KA: Representative Kuang An

Supervisor and issuing unit: Office of Safety Signs for Mining Products

Place of use: Non coal mines.

In addition, KY is the general type for mining, used in non gas areas of coal mines and some areas of low gas mines or non coal mines.