Over time, mine production began to decrease gradually until it stopped completely in the middle of the 14th century AD, after being covered by sand. Perhaps the reason for its decline was first due to the fear of its owners from attacks by the Beja and Arabs. Also, the production did not cover the expenses, then the workers in the metal land began to look for other activities, heading inland to the south.

From here, the Arab migration to the land of Nubia on the metal land did not stop in these northern regions of Nubia, but rather penetrated south to the capital of the kingdom of (Alwa) in the city of (Soba), and even further south. A residential city was found, which suffered for more than a century in the period from (825-941 AD) in (Khor Nabt), seventy miles northeast of the (Heba) station. It is likely that its inhabitants were engaged in raising camels and trading them. These camels played an important role in transporting pilgrims and goods between Upper Egypt and the Red Sea ports. In the metal land, many Arabic writings were also found in some places in Lower and Upper Nubia, the oldest of which dates back to the third Hijri century. Tombstones bearing Arabic names dating to 217 AH / 832 AD were also found, and in the Kalabsha area in 325 AH / 937 AD.

These Arab elements that migrated to those regions and then settled in this way soon left a clear impact on the history of the country and the lives of the inhabitants. They merged with the indigenous people, mixed with them, and lived alongside them. This mixing had the greatest impact on both the newcomers and the local people. We find that the newcomers had Nubian blood seep into them, and their complexion and their descendants became dark. Likewise, the local people mixed with Arab blood, embraced Islam, and learned the Arabic language.

This development of mixing, which has a great impact on the history of the country, archaeological research confirms it irrefutably.