I think the coal shortages in Germany were mainly transportation related,
...
Of wich coal shortage and especially at what point of time do you talk here ?
The coal shortage starting in late 1916 ? ... with the onset of the infamous, misconcepted, more devastating than building up "Hindenburg"-program ?
Well, there was - rather shortly - also a relative coal shortage/production drop during the first 2-4 month of the war in 1914 due to a lack of working force due to conscription
But this also started to cease again with the starting of the system of service exemptions for industry - weapons and ammo as well as mining - in october/november 1914 IIRC from Gerald Feldman : Army, Industry and Labor in Germany 1914-1918.
I think with Italy, from memory, the bugbear was its coal supply. The Italians needed a lot of it, and I don't think they got much of it from Germany in 1914.
...
Well, what about :
Instead of "parking" the 60.000 italian foreign miners and steel workers from Alsac-Lorrain in Hessia during the first 2 days of August and repatriating them after the finished deployment from last week of August onwards ...
why not employ them in the german coal mines of the Ruhr or Silesia, half of the by them "produced" coal for Germany, half of it for Italy ?