Lava pumps must now be directly connected to the foundries that create molten iron/copper. The molten metals can still be transported via pipes, so it's only the first stage of foundries that need to be built against the lava lakes.

Why? With all the cliffs and demolishers, Vulcanus has a theme of giving you lots of resources but little space to use them, requiring you to cram your factory into the irregularly-shaped areas available to you. This mod continues that theme, by requiring you to build your first foundries right up against the lava lakes, and cramming in the belts to move calcite in and stone out.

To make this work, the mod adds "heat-resistant offshore pumps" which are like regular offshore pumps except they require some tungsten carbide. Regular offshore pumps cannot be placed on Vulcanus.