Given your specifications of what this floor needs to be able to do, you have the choices of:
1) sinking heavy steel I beams to bed rock and then setting granite or volcanic basalt floor on top of those beams.
2) laying at least 4 foot thick granite or basalt on a bedrock base.
The reason most all current forges are built on I beam to bedrock/ steel reinforced concrete is that the concussions of hammer forges will destroy just about any material in a matter of weeks if not days.
The forges (50 ton and up) at the Caterpillar
Tractor plant in Decatur Il. shake the whole town when they are in operation.
If this is the type of work force you are describing, then you really don't have much choice.
Many of the old steel plants here in the US had pads for the forming machines with extremely tamped earth for the walk ways
Just about any paver currently available today is to thin to stand up to heavy duty, repetitive, concussions.
For an example, the Runways of Airports are a minimum of two feet thick, multi-layer steel reinforcement 12000 lb. concrete as a minimum so they will hold up to repeated heavy aircraft landings.
The steel landing decks of Aircraft Carriers are 2" thick solid steel supported by heavy I beams spaced 12" apart in two directions so they can withstand the forces of airplanes slamming into the deck to tail hook.
Your biggest issues for such "paving" is the vibrational forces that will resonate through the paving material in a sine wave. The material will be subjected to a rebound vibration as well as the concussion forces and the two will be almost equal in force.
If it was just being able to hold up weight, without any vibrational forces, then you could use multiple layers of high tensile pavers or stone with a thin layer of shock adsorbing material (just not spongey) between the layers.
A coke forge can be supported by tamped earth, just as the large, furnaces found in the Detroit area are/were.
Other than that piece of equipment, you might be able to use a stone/ ceramic paver covered with very thick steel as a floor but that will not meet the other specifications you mentioned since it will stain and rust unless always oiled.
You may find that what will work best are individual component pads with something else for between pad traversing (walking, rolling, etc.).
Redhawk