Land is probably the most valuable thing volcanoes produce. Volcanoes typically erupt and magma bursts out and when it flows on the land it forms newly required land. This land is made then by the magma cooling off.
Volcanoes can produce lava, ash, and gas.
Volcanoes do not produce uranium.
Volcanoes with high levels of water in their lava produce ash, those with dry lava produce no ash.
plate boundaries can produce volcanoes
plate boundaries can produce volcanoes
convergent
Shielf volcanoes generally produce "quiet" eruptions. Explosive eruptions are rare.
Sulfer and Igneous rock
igneous
No.
convergent
Plate (subductive).