The work refers to the work of Sandro Botticellis "Mappa dell´Inferno" (Chart of hell) which he painted in Florence at the end of the 15th century. Botticelli made a kind of illustration of Dantes "Divina Commedia" (The Divine Comedy) from the early 14th century.

Botticelli lays out his "Mappa" in a way that appears like a modern cut-away-view from an open-pit-mine. 

The axis runs from Jerusalem through the middle of the earth to the opposite side of the globe where a high mountain (Purgatory) is piled up.

In that sense, Dante knew that if there is an extraction there must also be an accumulation somewhere else.