Explanation:

- After mining, the huge holes left behind (often called open pits) are commonly repurposed.

- They are mainly used for storing mining waste materials, such as rock, soil, or even hazardous tailings.

- Some pits can fill with water, either naturally or for specific storage purposes.

- The options and explanation:

- Option 1: Wastewater storage – Sometimes correct, but not always the main use.

- Option 2: Waste and water storage – Broader and closer to typical use, but not a standard term.

- Option 3: Waste Disposal – Mining pits are most often used for waste disposal, like storing mine tailings or other debris.

- Option 4: Waste Storage – Also correct, but less precise than “disposal,” which is the standard term.

Correct Answer: Option 3 - Waste Disposal