Read more in Coal Tattoo:CHARLESTON, W.Va. -- The Obama administration on Thursday announced new water pollution guidelines aimed at greatly reducing what scientists say is the increasingly evident damage to Appalachian streams from mountaintop removal coal mining.U.S. Environmental Protection Agency officials said "no or very few valley fills" would be approved under new restrictions EPA regional offices will impose on state regulators under the federal Clean Water Act.In a detailed new guidance memo, EPA said it would more closely examine the potential impact of mining proposals on the electrical conductivity of streams, which is a strong measure of many harmful pollutants from mining and has been linked to aquatic life damage.EPA cited the findings of previous agency studies, peer-reviewed scientific papers and the conclusions of two new major reviews of mountaintop removal impacts by EPA's own Office of Research and Development.The EPA announcement drew harsh criticism from the mining industry, cautious comments from coalfield politicians, and praise from environmental groups and from water quality scientists."It's a very positive step forward," said Margaret Palmer, a University of Maryland biologist who has been studying mining impacts. "It's a clear sign that this administration wants to base policy on sound science."The Sierra Club called the EPA guidelines "the most significant administrative action ever taken to address mountaintop removal coal mining," while the National Mining Association called EPA's science "both flawed and limited in its findings and application as justification for today's announcement."EPA released its guidance more than a year after initially announcing a crackdown on mountaintop removal and beginning more detailed permit reviews that have drawn intense criticism from the industry and its political supporters.Sen. Robert C. Byrd, D-W.Va., said the EPA announcement "will hopefully now have everyone reading off the same page" and provided a "clearer, concise policy on moving forward with mountaintop mining permits and water quality issues."In mountaintop removal, coal operators use explosives to blast off entire hilltops and uncover valuable low-sulfur coal reserves. Leftover rock and dirt is shoved into nearby valleys, burying streams.Industry officials consider the method to be highly efficient and the only way to reach some thin seams of Appalachian coal. But critics point to the fewer number of workers mountaintop removal needs, and a growing body of science shows that forests, water quality and community health are threatened by mining practices.In the case of conductivity, a widely cited EPA study published two years ago found that levels above 500 on a scaled measured in micro-siemens per centimeter could impair aquatic life in streams.Scientists use conductivity as a key indicator of stream health and of the presence of other important pollutants such as chlorides, sulfides and dissolved solids. Still, EPA and most Appalachian states do not have numeric water quality standards for conductivity.In a report issued Thursday, EPA said its new research has found that only conductivity levels below 300 can be assured of not causing unacceptable damage to aquatic life.So in its new guidelines -- effective immediately but also subject to public comment -- EPA essentially says it will not allow states to issue water pollution permits for mines expected to cause conductivity levels to increase to more than 500. If conductivity is predicted to increase between 300 and 500, EPA said, it will work with states and mining companies to put in place protections to keep those levels from going higher.EPA said the guidelines are intended "to protect 95 percent of aquatic life and freshwater streams in central Appalachia."Randy Huffman, secretary of the West Virginia Department of Environmental Protection, said he was glad to see EPA finally issuing some sort of written guidance that mining companies and DEP can debate and discuss with federal officials.But Huffman said he was also concerned about the usual nature of the "interim final guidelines," which while effective immediately are intended to be insulated from legal challenge by being labeled as not a final EPA action."That also sends some kind of message," Huffman said. "It's almost like answering the question and then going back and formulating the question."Huffman said his agency was also concerned about the 300-conductivity level targeted by EPA, though DEP itself has in several stream studies indicated conductivity above that threshold could cause stream impairment.During a conference call Thursday afternoon, EPA Administrator Lisa Jackson told reporters, "Let me be clear. This is not about ending coal mining. This is about ending coal mining pollution."Jackson cited the case of the Hobet 45 mountaintop removal permit, in which EPA pressure pushed the company to cut stream impacts in half but still be able to mine almost all of the coal it originally planned. While Hobet 45 technically does not have "valley fills," roughly 3 miles of streams would still be buried when the company mines through streambeds."Minimizing the number of valley fills is a very, very key factor," Jackson said. "You're talking about no or very few valley fills that are going to meet standards like this."The intent here is to tell people what the science is telling us, which is it would be untrue to say that you can have numbers of valley fills, anything more than say, very minimal valley fills and not expect to see irreversible damage to stream health."That's just the truth of it," Jackson said. "That's the science of it."Reach Ken Ward Jr. at firstname.lastname@example.org or 304-348-1702.