Simplify the following text for a Grade 10 native English-speaking person.
Original: Travira 's aircraft are used for long-term deals with major mineral companies , such as ExxonMobil , West Natuna Consortium , and mining companies in Sumbawa and East Kalimantan .
Simplified: Travira 's aircraft are used by big mineral companies including ExxonMobil and West Natuna Consortium . They are also used by mining companies in Sumbawa and East Kalimantan .