Explain why new copper extraction methods are needed as high-grade copper ores become scarce. (HT only)

In the subtopic Alternative methods of extracting metals, this learning objective focuses on explain why new copper extraction methods are needed as high-grade copper ores become scarce. (HT only). Within Using the Earth's resources and obtaining potable water, students should explain this idea in the exact curriculum context rather than as an isolated fact. Approved keywords for this objective include HT only and copper ore. high-grade copper ores means copper ores that contain a high percentage of copper, making them economically viable for extraction. Avoid students often think that high-grade copper ores are completely depleted, rather than understanding that they are becoming scarce; instead emphasize that high-grade copper ores are still available but in limited quantities, necessitating the development of new extraction methods. For exam answers, focus on the reasons why high-grade copper ores are becoming scarce and the implications for extraction methods.