Lava is a liquid block which can be gathered by Buildcraft Pumps or a bucket, and can only be placed by a bucket. It damages players and mobs, and sets them on fire. It can also set flammable objects within four blocks on fire. A player wearing Nano Armor or Quantum Armor will not take damage. Any items dropped into Lava will be destroyed, so dying in Lava will make a player lose all of his/her items. Lava can be pumped in to Waterproofed Pipes/Liquiducts , which then can be stored in Tanks, processed by a Combustion /Magmatic Engine to make MJ , or turned into Lava Buckets for use in an Industrial Centrifuge . Many players use Lava Buckets to make Lava Cells , which can power Geothermal /Thermal Generators to produce EU. Lava Buckets can also be used as fuel in Furnaces , or to fuel a Turtle . If Lava makes contact with Water, it will either make Cobblestone,Obsidian, or Smooth Stone.
To pump Lava, one should use Buildcraft Pumps, and then output them into tanks. A common practice is to pump into Ender Tanks, which allows remote pumping into a storage base. This idea is sometimes even extended to the Nether, as Ender Tanks do allow for Inter-Dimensional Storage, and that the Nether has almost infinite Lava. Remember to put a World Anchor down though! The Lava outputed in the storage base has many uses, from making MJ power to power a Quarry , Lava Cells to make EU via Thermal Generators, or a suprise flood attack on friends. Another option is to use a Tesseract .
Lava also has another use: Infinite Cobblestone Generators! One option is to use an Igneous Extruder. Another way to generate stone is with a vanilla Stone Generator.