In the Jedi Academy Trilogy, Han was briefly imprisoned in the spice-mines of Kessel, where he had a near-lethal encounter with the energy spiders that make the spice (as webbing). After he escaped, Lando bought out the spice-mining operation. In Fate of the Jedi: Outcast, Lando mentions he's been trying to expand, but is having difficulties...
Lando: Efforts to transplant colonies of the energy spiders that produce the stuff haven't been very successful.
Han: You're trying to get them to survive on other planets?!
Lando: Yes, but they just stop feeding and dieó