I grew up in Western Pennsylvania (coal country), and I can remember an orange-tinged stream close to my grandmother’s house. The cause was Acid Mine Drainage, which contaminates waterways near coal mines with iron, creating biological dead zones.
So I was particularly interested in an article in the February 2014 issue of Ceramics Monthly. In this article, which I am excerpting from today, Skip Sensbach explains how one organization is turning this environmental hazard into a usable resource while cleaning up waterways.- Jennifer Harnetty, editor.
Iron is a common element that is found in most of the ceramic materials we use. From clay to glazes, we come in contact with iron on a daily basis, usually in the form of iron oxide. Iron is a useful and important element in forming the color of our clays and glazes as well as in some instances acting as a flux. For many ceramic artists, the need to add iron oxide to clay and glazes usually ends up with a phone call to a clay supplier to order several pounds of the material. The iron oxide is then shipped, possibly traveling over many miles before arriving at the studio. However, for artists who live in an area that has a history of mining, a more environmentally friendly source of iron oxide might be in your own back yard.
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While iron is desirable for the formation of color in ceramics, it is not desirable in our local environments. Acid mine drainage (AMD) is a source of water pollution that plagues areas that have old or existing mines. Northeast Pennsylvania has a rich history of coal mining and even though most of the mines are no longer in operation, our area is left with the residual effects; water contaminated by iron. The iron enters the environment either through bore holes, drilled to relieve mine water pressure, or through rain and melting snow run-off seeping through leftover culm material.
According to information published by the Earth Conservancy, the environmental effects are devastating to local stream and river ecosystems. These waterways are usually colored yellow and orange, which is caused by the chemical relation between the iron-rich discharge and oxygen. The resulting iron oxide particles color and affect everything in the waterway, including rocks, trees, plants, and wildlife that frequent these sites. This contaminated water, in essence, creates a biological dead zone.
There are treatment solutions that can benefit not only the local environment but also ceramic artists. Robert Hughes is the executive director of the Eastern Pennsylvania Coalition for Abandoned Mine Reclamation (EPCAMR), a public, non-profit organization located in Ashley, Pennsylvania. Hughes and the EPCAMR have been working on solutions to this problem since 1996. According to Hughes, one of the processes they use to clean the water is to create a “passive” treatment system. This consists of the mine water flowing through a device that injects oxygen into the water before it goes into a containment pond. The oxygen speeds up the chemical reaction and the iron particles are deposited as sludge at the bottom of the pond. The water then drains off into the first treatment cell where further oxygenation takes place and wetland vegetation helps trap the particles. The water then flows to another basin where the remaining iron particles are removed.
The clean water is then released back into the environment. What is left behind is an iron oxide sludge that is collected and dried into a packed yellow powder. The powder is then sifted, ground down, and baked to enhance the color of the oxide, which can range from yellow and orange to a deep red. The EPCAMR then sells this material to artists for a variety of uses. For a ceramic artist, this powder is an excellent source of iron oxide, which can be incorporated into glaze and clay recipes. The organization tests this iron oxide to ensure the chemical purity, thus it is free of other potentially dangerous metals like aluminum, cadmium, and arsenic.
If you live in an area affected by the mining industry, I suggest looking into local organizations that might be working to clean these sites up as a source of ceramic material. If a local source is unavailable, you may want to try the colorant produced by the EPCAMR. They can be contacted through their website, www.EPCAMR.org.
the author Skip Sensbach is an artist and teacher living in Dallas, Pennsylvania. He is the owner of Green Dog Pottery, and teaches at Marywood University and Misericordia University