DESPITE protests from nature-lovers, passage of the strip mine "mitigation" bill by the 1998 Legislature may be the best thing that could have happened to West Virginia - because it may lead to real studies of long-term effects of huge valley fills that bury miles of streams and headwaters.The U.S. Environmental Protection Agency blocked a permit for a new A.T. Massey mountaintop removal mine, partly because federal regulators don't think the new mitigation law is sufficient to protect water quality.If the state Division of Environmental Protection cannot address EPA's concerns in 90 days, EPA will have sole legal authority to approve or deny the permit.And, by law, before EPA can approve a permit, the agency must conduct a full environmental impact study on the proposed valley fills. Since EPA has implied that it may block all permits issued under the new law, these environmental impact reports may have to be done for each new valley fill proposed by the coal industry.At last, a comprehensive study of the long-term, cumulative effects of valley fills will be undertaken.Coal companies blast and bulldoze the tops off mountains to get at the coal beneath. Tons of "spoil" - stuff that used to be a mountain - are dumped into valleys, leveling them.Regulators, both state and federal, have admitted they don't know what this does to streams in West Virginia, despite the fact that the federal Surface Mining Control and Reclamation Act prohibits regulators from issuing permits when they do not know the cumulative hydrological impacts.It's ironic that a really bad bill making it cheaper for coal companies to fill valleys may actually result in a long-needed study of those fills.The news is especially welcome since the task force appointed by Gov. Cecil Underwood to study mountaintop removal appears to be tilted strongly in favor of industry.Only one environmentalist with any credibility - John McFerrin (a Gazette contributing columnist) - was appointed to the panel. Cindy Rank, mining chair of the West Virginia Highlands Conservancy and one of the most knowledgeable and persistent critics of mountaintop removal mining, was left off.If Underwood had wanted to show he's serious about really studying this issue, Rank would have been included.Unfortunately, that leaves the task to the feds. Fortunately, EPA appears willing to take it on.