Is it permissible to obtain an interest-bearing loan from a conventional bank to finance a marble extraction project, knowing that the project will repay the loan within six months?

That is not permissible because it is usury (riba), and Allah has forbidden usury in His Book, saying: "Allah has permitted trade and forbidden usury." And He said: "Allah destroys usury and gives increase for charities." Then He warned those who consume usury of a war from Allah and His Messenger. The Messenger of Allah, peace and blessings be upon him, forbade it, and cursed its perpetrator, its consumer, its provider, its scribe, and its two witnesses. He also mentioned consuming usury as one of the seven destructive sins. It is not permissible to engage in it except out of dire necessity. The solution is to seek legitimate financing methods, such as Murabaha compliant with Sharia.