The tell Atchana was excavated by a British team led by Sir Leonard Wolley during years 1937-1939 and 1946-1949. 17 archaeological layers cover the period from the 21th century BC and the 13th century BC.
A team from the University of Chicago, directed by Aslihan Yener, took over the excavations since 2003. About 500 cuneiform tablets were exhumed there.
Mari archives evoke this city under the name of Alahtum. Thus, a series of tablets show that Zimri-Lim bought the city of Alahtum.
The archives of Hattusa mention that Allah to has been destroyed during the second campaign of Hattusili I. The most significant is the treaty tablet referenced CTH 135 from Hattusa, AT 2 in the Alalakh archives, which is an agreement between the Kings of Mukish, Niqmepa and Tunip not far. The Hittites intervened to secure the borders between Ugarit, Tunip and Mukish which capital was then Alalah.
It is on this site that was found the statue of Idrimi :
Some Alalakh tablets show a distinction between town and country of Mukish. Thus the tablet 350 of Wiseman is a list of sheep: 115 belong to Alalah; 402 sheep to Mukish; 250 men of Sagaz; and 268 men of Samanu.
It is not at all sure that Mukish matches the plain of Amuq. I rather think that this is, through the use of the Orontes, a maritime country more situated West. The exploitation of the river port, on the road between the Mediterranean and Mesopotamia, was the main function of this city.
My notes of veracity :
Tell Atchana is called Alahtum in the archives of Mari: 3/5
Tell Atchana was the city of Alalakh or Alalah: 5/5