Carthaginian trade-relations with the Iberians, and the naval might that enforced Carthage’s monopoly on this trade and the Atlantic tin trade,[110] made it the sole significant broker of tin and maker of bronze in its day. Maintaining this monopoly was one of the major sources of power and prosperity for Carthage; Carthaginian merchants strove to keep the location of the tin mines secret.[111] In addition to its role as the sole significant distributor of tin, Carthage’s central location in the Mediterranean and control of the waters between Sicily and Tunisia allowed it to control the eastern peoples’ supply of tin.

Source: Ancient Carthage – Wikipedia