The seven technicians in the coal mine refer to those.

What you want to ask is who are the six technicians in the coal mine They are gas inspectors, underground blasters, safety inspectors, main hoisting operators, underground electrical fitters and shearer drivers.

According to the query of coal mine safety net, its six posts refer to six categories: gas inspector, underground blaster, safety inspector, main hoist, underground electrical fitter and shearer driver.

Coal mine is a reasonable space excavated by human beings when mining geological strata rich in coal, which usually includes roadway, adit, mining face and so on. Coal is the most important solid fuel and a combustible organic rock.