Anglo American is using gypsum by-products from its mining operations to build energy-efficient houses for its workers, CNN reports.
The company’s South African operations are mixing the gypsum with cement to make bricks, which it has used to build 62 houses, and Anglo American is aiming to provide for all 400 of its employees in the city of eMalahleni, which suffers from a housing shortage.
Head of sustainable development Peter Gunther said that because gypsum is a strong binding agent, the bricks contain very little cement, saving an average of three tons of carbon dioxide per home. About five percent of man-made CO2 emissions come from cement production, the Cement Sustainability Initiative says.
Gunther says the bricks are also harder than most traditional cement bricks, and provide better heat and sound insulation.
Each home uses about eight tons of gypsum, and Anglo American is removing about 200 tons of the material from its waste water each day.
In the U.S., where coal produces nearly half of all power generation, coal-fired plants create 136 million tons of coal ash a year, of which companies recycle about 50 million in products including concrete, cement and gypsum wallboard.
The EPA is proposing national rules to safely dispose and manage coal ash from coal-fired power plants. The proposed rules would also support beneficial reuse or recycling of coal ash in the manufacture of materials such as cement, concrete and asphalt.
Depending on how those regulations are crafted, coal ash could be regulated like a hazardous waste, a move that has raised concerns among businesses. Utilities have already begun lobbying the White House on the potential effect of the EPA’s proposed rules.
But last month the House of Representatives passed a bill to block the proposed rules, instead voting to allow states to enforce federal ash standards, without requiring them to do so.