MB4 263a: Borrowed Items and Hilchos Techumim (397:11-16)

If you borrow an item from another whose techum does the item obtain? What if the item was promised to the borrower before Shabbos but he doesn't take possession of it before Shabbos?

If someone asked to borrow salt/water/spices to cook on Yom Tov who's techum does the finished dish follow?

Determining the techum for a flame, coal, or water from a well/pit. What if the well is owned by the residents of a city?

Techumin for a hefker item.

Flowing water (e.g. a spring or a river) who's source is outside the techum.

Filling up water for someone else.