Answer:
Father de Mora asked the monk not to tell anyone about the gold because he wanted to keep it for himself. He was greedy.
Step-by-step explanation:
According to the History of America when Father de Mora found out about the gold mines he asked the monks not to tell anyone about it. Father de Mora used slaves and prisoners to dig the mines for ten years in secrecy.
He did not tell anyone about the gold because he was greedy and wanted to keep all the gold for himself. His motive was selfish gain and greed.