How does mine drainage occur?

Plants naturally grow in and around lakes, but sometimes lakes and ponds can get an overgrowth of plants, algae, or bacteria. In many cases, humans are responsible. Chemicals that are used on lawns and in agriculture (like nitrogen and potassium) wash into our water systems. Once there, plants and algae have a feast on this “food.” Sometimes overgrowths of cyanobacteria (called “blooms”) can make...

When sulfurous, sulfuric, and nitric acids in polluted air and rain react with the calcite in marble and limestone, the calcite dissolves. In exposed areas of buildings and statues, we see roughened surfaces, removal of material, and loss of carved details. Stone surface material may be lost all over or only in spots that are more reactive. You might expect that sheltered areas of stone buildings...

Yes. Crater lakes atop volcanoes are typically the most acid, with pH values as low as 0.1 (very strong acid). Normal lake waters, in contrast, have relatively neutral pH values near 7.0. The crater lake at El Chichon volcano in Mexico had a pH of 0.5 in 1983 and Mount Pinatubo's crater lake had a pH of 1.9 in 1992. The acid waters of these lakes are capable of causing burns to human skin but are...

Methane (a gas composed of carbon and hydrogen) is produced two ways: Through biologic decomposition of organic matter at shallow depths. Swamps, landfills, and even shallow bedrock are some settings where this occurs. Methane can also be derived over millions of years by high pressure and high temperature processes that produce fossil fuels deep underground. Examples include coal deposits and oil...

The primary methods used to extract minerals from the ground are: Underground mining Surface (open pit) mining Placer mining The location and shape of the deposit, strength of the rock, ore grade, mining costs, and current market price of the commodity are some of the determining factors for selecting which mining method to use. Higher-grade metallic ores found in veins deep under the Earth’s...