An abandoned Indiana coal mine spoil bank contains chunks of pyrite minerals. Under constant erosion and weathering, the pyrites leech large amounts of sulfuric acid (H₂SO₄). The spoil banks are also mixed with large quantities of basic limestone and clay carbonates. What should occur over time?

Question

Quizplus · Accepted Answer

Over time, the pH levels will vary depending on the amount of acid leached from the pyrite minerals and the amount of basic limestone and clay carbonates present. Initially, the pH levels may be more acidic but eventually, the acid will be neutralized by the bases leading to the pH levels drifting back towards 7.0. However, the pH levels will still be spotty and vary over time due to the ongoing erosion and weathering of the pyrite minerals.

An Abandoned Indiana Coal Mine Spoil Bank Contains Chunks of Pyrite