In very rough terms it takes about one tone of coal to convert one ton of ore into pig iron, the base metal for further steel production, and further production consumes more coal as well as various other minerals for alloys. Thus the history of steel is that it is economic to ship ore or coal either way ut as an industry it flourishes where the coal is and is influenced greatly by transport costs with waterborne being the most economic, therefore you look for water routes, ports, rivers and coal seams to locate the blast furnaces. Spain could develop a decent steel industry but its coal does not out produce its ore, thus I would guess on that disparity alone it exports ore and has a tiny local serving steel industry. After all the coal is being used for far more stuff than firing blast furnaces and ovens to make steel. And we have no idea if the domestic industries exist to use it. This is why so many mineral rich countries still end up industrially deficient. It is more complex than merely gaining the capital to build it. My guess for the fall in ore exports during the war is that its natural export markets simply cannot afford the bottoms to move the ore. Thus why a domestic shipping industry has value too.
In some alternate war with French ore captured but the rest of its industry not occupied, i.e. a far more limited German drive into French territory, France could buy ore it o longer mines, but France still needs coal, something it can buy from Britain. Using our pedestrian economics that argues for France having an even better ability to sustain her war effort on the industrial side. But that also means she spends gold or gets credit to buy both coal and ore and shipping, to the detriment of other things, and uses manpower to do it. The knife cuts both ways, France is either making more stuff with a smaller Army or buying what it needs and filling the ranks. Gross generalizations that serve the balancing we do on a grand sweep. And this is how I settled on a vague draw where Germany does not drive through Belgium, France is better off and can reorient her industry, but it is not a panacea, Germany might still secure just the ore mines or threaten then enough to strangle production, but she also might gain no UK at war, no blacklisting that sticks with neutrals as she is not the evil aggressor, etc. And Germany has a shipping industry that could get to that ore if needed, if the RN stands neutral and those bottoms reflagged USA or Swiss, we spin off into some speculative territory. Could France impose a blockade?