The first sign says: "Use proper lifting techniques, in order to avoid back injury". The second sign warns against grinding incendiary materials in the machine (aluminum powder, and magnesium are the principle ingredients in thermite, an incendiary that can melt metal). It also warns against grinding materiels that could precipitate a dust explosion (flour, for instance). A dust explosion is when a dense concentration of flammable particles in the air, are detonated by a spark, or other heat source, creating an instant fireball effect. I can't help you with the "flammable coolant". I think these signs were originally in a language different from English, and may have suffered in the translations.