It is part of the sunnah of Hajj that the imam pray Dhuhr, Asr, Maghrib, Isha, and Fajr at Mina... the hadith continues.
من سنة الحج أن يصلي الإمام الظهر والعصر والمغرب والعشاء الآخرة والصبح بمنى… الحديث.
Ibn Khuzayma (2800) narrated it from Yusuf bin Musa, who said, Jareer narrated to us, from Yahya, from Qasim bin Muhammad, from Abdullah bin Zubayr, who said (and he mentioned it). It will come in full in the chapter on what constitutes the first release from restrictions.