What is the term for equipment that has been checked for safe use in a coal mine?

The term "permissible" specifically refers to equipment that has been evaluated and meets the safety standards necessary for use in a coal mine. This designation indicates that the equipment has undergone rigorous testing to ensure it does not pose a risk of igniting flammable gases or dust, which is a significant concern in mining environments.

In the context of coal mining, where hazardous conditions can heavily influence safety, equipment labeled as permissible ensures miners can operate under safer conditions. The use of this term also implies compliance with relevant safety regulations and standards set forth by governing bodies to protect miners.

While "approved" and "certified" may convey a sense of safety, they do not carry the specific connotation related to the unique dangers found in coal mines, which is foundational to the distinction of permissible equipment. The term "permitted" may also be associated with various authorizations but lacks the particular focus on safety in mining operations that "permissible" conveys.